Assessment of crown woody biomass in <Emphasis Type="Italic">Eucalyptus grandis</Emphasis> and <Emphasis Type="Italic">E. globulus</Emphasis> plantations

Young trees were harvested to explore non-destructive methodologies to estimate live branch dry weights in young fast-growing Eucalyptus species under different spacing and fertilizer treatments. Branch growth can vary with silvicultural management such as spacing, fertilizing and thinning, and over relatively short periods in response to environmental conditions. Many published regressions based on standard measurements of height and diameter are site, age and treatment specific. The aim of this study was to improve our capacity to predict woody crown dry weight, based on stem measurements, and to minimize (or eliminate) treatment effects on the resulting model. In young trees, branches are temporary support structures for foliage and are often discarded as the base of the green crown rises. As temporary structures they represent an investment of biomass and nutrient elements, and are subject to selection pressures to maximize the return on investment by the tree. Trees were harvested from existing plantation experiments located in south-eastern Queensland for E. grandis W. Hill ex Maiden (ranging from 0.28 to 15.85 m in height, to 5 years old) and south-western Australia for E. globulus Labill. (0.10–34.4 m in height, to 10.2 years) in order to examine the impact of spacing, nitrogen and phosphorus fertilization on early growth. Relationships to estimate crown woody biomass from non-destructive measurements were developed, and these relationships tended to have different slopes and intercepts for trees with predominantly juvenile foliage and those with intermediate or adult foliage. Dry weight of whole-crown live branch wood (W_branch) was related to heights and/or diameter at breast height (D_BH), but the regressions parameters were different, depending on treatment. The relationships became more generic (i.e. less dependent on treatment effects) between W_branch and stem sectional area at the height of the base of the green crown (SA_CB), consistent with the pipe model theory (R² > 0.91 for the two species for trees with intermediate/adult leaves). However, W_branch was more closely related again to the stem volume above the base of the green crown and treatment effects were not significant (V_Con,gc, R² > 0.93). Branches exit the stem below the green crown, and for E. grandis the best relationship was on stem volume above the lowest live branch (V_Con,llb, R² 0.94). Limited sampling from four other species with similar or contrasting crown characteristics indicated that the relationship could be applied quite generally. Individual E. grandis branch woody dry weight was closely related to the conical volume of the main (first order) branch (V_con,br, R² 0.98₎. The whole crown equivalent, branch woody dry weight plus stem dry weight above the lowest live branch, was also closely related to the stem volume within the woody crown (V_Con,llb, R² 0.97–0.99). While the slope of this relationship was still significantly different between trees with juvenile and intermediate/adult foliage, it had a similar form, suggesting that trees with juvenile foliage allocated a different proportion of their woody biomass within the crown to branches than older trees.     

The populations and distribution of <Emphasis Type="Italic">Pieris japonica</Emphasis>, a poisonous tree protected from herbivore browsing pressure,increase slowly but steadily

Pieris japonica is a poisonous tree species that is rarely eaten by herbivorous animals, a fact that could enable the expansion of its distribution range and influence ecosystems into which it encroaches. In a regional-scale study, 300 P. japonica trees from 13 populations were sampled at the University of Tokyo Chichibu Forest, Japan, and were analyzed using 11 microsatellite markers. Genetic differentiation among the populations was low (F _ST = 0.022 and G′ _ST = 0.024). A plot (30 × 30 m) was established for a fine-scale study, in which all P. japonica trees and saplings were measured and genetically analyzed using the microsatellite markers. Using this approach, we detected 84 genotypes among the 121 P. japonica trees in the plot. A few genotypes had expanded by more than 5 m, indicating that the ability to reproduce asexually could facilitate P. japonica trees to remain in a given location. Autocorrelation analysis showed that the extent of nonrandom spatial genetic structure was approximately 7.0 m, suggesting that seed dispersal was limited. KINGROUP analyses showed that 44 genotype pairs were full siblings, 23 were half-siblings, and 40 were parent-offspring. Only 32 seedlings were observed, of which 15 had reproduced asexually. The number of P. japonica trees has been increasing gradually for more than half a century in our study areas.     

Yield and Nutrient Content of Chestnut (<Emphasis Type="Italic">Castanopsis piriformis</Emphasis>) in Natural Central Highlands Forests,Vietnam

Chestnuts have historical importance as a food source worldwide. Planting of chestnuts has focused on a few species, including Castanea dentata, Castanea sativa, Castanea mollissima, and Castanea crenata, although others species are also edible. Castanea species are members of the beech family (Fagaceae) and are native to tropical and temperate areas. In this study, the yield and nut quality of Castanopsis piriformis in natural forests of the Central Highlands of Vietnam were investigated to provide evidence that C. piriformis is worth growing as a food species. Data were collected from 12 plots of 50 m × 50 m size located in four altitude zones. Nuts were collected from three to five chestnut trees in each plot judged to be of typical sized based on diameter at breast height and crown diameter. Average dry yield of nuts was found to be elevation-dependent, being highest at 500–1000 m (1152 kg/ha/year), decreasing to 815 kg/ha/year below 500 m, and to 770 kg/ha/year at 1000–1500 m. The lowest yield was observed at above 1500 m (252 kg/ha/year). Protein and lipid contents in the kernels of C. piriformis chestnut were 4.4 and 0.1 %, respectively. Glucose accounted for 73.1 % and was significantly higher than that of commercially grown Castanopsis boisii chestnuts in Northern Vietnam. With the current price of 0.6 US$/kg nuts, collecting nuts growing in natural forest can bring at least 480 US$/ha/year to local people. These results indicate the possibility of growing and consuming C. piriformis chestnut as a crop to decrease poverty. However, governmental support is required for the sustainable development of C. piriformis.     

Tree Quality in Agroforestry Systems Managed by Small-Scale Mayan Farmers in Chiapas,Mexico

Increasingly, plantations for food, fiber and wood, are necessary to provide a growing world population. Agroforestry systems become more and more important, however these systems usually develop in marginal conditions, limited land, restricted funding, occasional technical support and above this, there is limited documentation and evaluation of innovated traditional systems in indigenous and small-scale contexts, which challenge forest scientists. The aim of this research was to assess the quality of trees in plots managed by Mayan indigenous farmers who planted agroforestry systems with fine wood species to increase the value of land and labor in localities with highly-marginal social conditions in Northern Chiapas, México. Twenty oldest plots were selected within a group of previously established plots (eight with improved fallow, six with shaded coffee and six with maize crop associated to trees) where forest inventories were carried out in nested 100 and 1000 m²-circular plots. In all plots tree diameter, height, quality indicators and the incidence of the pest Hypsipyla grandella were measured. Trees in the maize-associated-to-trees system are favored by the practices applied to annual crop during the first 3rd–5th years, a period in which they are free from the interference of other trees and benefit from favorable light conditions, weeding and a higher intensive care from the farmer while shaded coffee and improved fallow have higher tree densities and a more closed canopy condition than maize associated to trees. In consequence, maize associated to trees shows 68.1 % stems with good form; shaded coffee and improved fallow averaged 40.5 and 39.7 % of good quality stems, respectively; improved fallow exhibited a greater number of suppressed trees than shaded coffee and maize associated to trees (p < 0.0001). In addition, maize associated to trees showed the highest proportion of trees with commercial value with 56.9 %, followed by improved fallow with 28.2 %, and shaded coffee with 11.8 % (p < 0.0001); the rest were trees with domestic uses. However, maize associated to trees significantly result with high incidence of H. grandella probably due to the crown exposure. Timber volume averaged 92.9 ± 68.9 m³ for improved fallow, 77.3 ± 24.8 m³ for shaded coffee, and 52.5 ± 39.7 m³ for maize associated to trees. The value of the fine wood represents increment in income, variety of products and self-employment for households. Nonetheless, improved fallow and coffee plantations might benefit from the elimination of competitors from larger trees to favor promising immature ones and pruning, while maize crop associated to trees might benefit from opportune pruning for controlling the stem borer as well as tree replacement to achieve long term replacement and harvesting.     

Growth of planted seedlings inside protective sleeves under strip openings of different widths in a post-agricultural forest

Many second growth forests have poor regeneration and in some spatial and economic context, such as post-agricultural forests, it may be beneficial to increase tree diversity. We planted seedlings of yellow birch (Betula alleghaniensis) and bur oak (Quercus macrocarpa) in strip openings of 3, 6 and 9 m width to control light. Individual mesh sleeves were used to reduce browsing pressure but they also reduced available light for seedlings: a large mesh and a small mesh sleeves were tested in each opening. Available light for seedlings ranged from 5 to 46% of full sunlight. First year growth was almost non-responsive to all treatments for both species, but birch showed strong responses during second year. Birches in the large mesh sleeve and the 9 m opening had the largest height and diameter increments, while those in the small mesh sleeve and the 3 m opening had the smallest increments. Small mesh sleeves increased the height over stem diameter ratio for both species. Treatments affected several other morphometric variables of birch but none of the oak. More time is needed to assert if bur oak can be a candidate species for enrichment planting. We recommend strip openings of 9 m width and large mesh sleeves, for protection against deer browsing, while controlling neighbouring competition, to promote artificial regeneration of hardwood species.     

Introduction of Raikhanim (Ficus semicordata) in a Maize and Finger-Millet Cropping System: An Agroforestry Intervention in Mid-Hill Environment of Nepal

Fodder trees are integral part of farming system in the hills of Nepal, but designed agroforestry interventions targeted to particular trees and crops are not widely available. This paper examines the joint productivity of an agroforestry practice in which Raikhanim (Ficus semicordata) is planted in a maize (Zea mays) and finger-millet (Eleusine coracana) cropping system at Keware Bhanjyang of the western mid-hills of Nepal. Raikhanim seedlings were planted in a row on terrace risers 2, 4 and 6 m apart in ordinary farming conditions, in a randomized block design with three replications. Maize and finger-millet were grown on the terraces as intercrops with a control plot without trees on risers in each replicate. Growth parameters of Raikhanim—height, diameter at 30 cm above ground (D₃₀) and survival rate—were recorded annually in December until trees were lopped for fodder biomass, and crop yields were measured to determine tree-crop interaction effects. Tree height and D₃₀ differed significantly between spacings until trees reached the lopping stage 3½ years after planting, with the highest growth in 4 m spacing. Tree lopping checked the height growth but the diameter growth continued to increase and differed among spacings after lopping. Fodder biomass increased with tree age and was highest under 4 m spacing (7.294 t/ha) followed by 6 m (5.256 t/ha) and 2 m (3.84 t/ha). Finger-millet yield in the experimental plots decreased with tree age due to shading effects, while maize yield was not substantially affected. Among spacings, control plots produced the highest finger-millet yield (1,624 kg/ha) while the 6 m spacing produced the highest maize yield (2,463 kg/ha). It is concluded that planting Raikhanim at 6 m intervals will produce additional fodder without significant effect on maize yield and only a moderate effect on finger-millet yield. The agroforestry practice of planting fodder trees on under-utilised terrace risers is a viable option for mid-hill farmers for simultaneous production of fodder and cereal crops while sustaining the hill farming system.     

Effect of light,fire and weed control on establishment of <Emphasis Type="Italic">Pericopsis elata</Emphasis> Harms regeneration

Pericopsis elata (a.k.a. African teak) is one of the most valuable timber species in Central Africa. Like other shade intolerant tropical tree species, P. elata could play a vital role in economic development, and ecological sustainability, but regenerates poorly following selective logging. Now endangered, there is a critical need for sustainable silvicultural systems to restore this once prominent timber species. To assess management options for P. elata we analyzed growth performance and survival in primary and secondary forest plots under burning and weeding treatments in Yoko Forest Reserve, Ubundu Democratic Republic of Congo. We transplanted nursery-grown seedlings of P. elata to experimental gaps and followed their growth and survival for 1 year. Seedlings in large canopy gaps 50 × 50 m were taller (mean difference; P = 0.006) and more likely to survive (mean difference; P < 0.001). Weeding improved both diameter (P = 0.024) and height (P = 0.007) growth rates; however, burning alone did not significantly improve the performance of P. elata seedlings. Our data suggest that P. elata regeneration is compatible with shelterwood harvesting and traditional swidden agricultural systems widely practiced in the region.     

Vegetative propagation of <Emphasis Type="Italic">Litsea monopetala</Emphasis>, a wild tropical medicinal plant: Effects of indole-3-butyric acid (IBA) on stem cuttings

In this study we investigated the rooting ability and the growth performance of juvenile single-node leafy stem cuttings of Litsea monopetala (Roxb) Pers. collected from two mature mother trees preserved in the hill forest of Chittagong district, Bangladesh. The rooting ability of cuttings was studied under 0%, 0.1%, 0.2% and 0.4% indole-3-butyric acid (IBA) treatments. Significantly better rooting response (p ≤ 0.05) was observed with 0.1% IBA compared to control (0% IBA). The mean number of roots and the length of the longest root of cuttings in different treatments showed no significant difference (p≤0.05). After transfer into polythene bags from non-mist propagator, rooted cuttings treated with 0%, 0.1% and 0.2% IBA demonstrated the highest (100 ± 0.00%) survival capacity. The mean number of shoots developed in cuttings in the polythene bags in first three weeks varied significantly (p≤0.05) among the treatments. Effects of three fertilizer treatments, viz. T0 (no fertilizer), T1 (10g Urea, 20g TSP, 10g MOP dissolved in 1 L water) and T2 (10g Urea, 20g TSP, 10g MOP dissolved in 2 L water) on initial growth ofstecklings were also measured over a 90-days period. The increment of leaf area of stecklings was significantly higher (p≤0.05) under T0 compared with that under T1 and T2 while the increment of stem length, collar diameter and root biomass varied insignificantly among different fertilizer treatments. The results suggest that rooting juvenile single-node leafy stem cuttings could be an effective mean of regenerating L. monopetala. The application of 0.1% IBA concentration is recommended for rooting of juvenile leafy stem cuttings and application of fertilizer appeared unnecessary for the subsequent growth of stecklings in polythene bags.     

Seed bank and regeneration dynamics of <Emphasis Type="Italic">Emmenopterys henryi</Emphasis> population on the western side of Wuyi Mountain,South China

Emmenopterys henryi Oliv. (Rubiaceae) is an endangered tree species that is native to China. The wild populations of E. henryi have declined rapidly because of its poor natural regeneration, but the actual regeneration processes are not yet understood. In field tracking surveys and experiments in the Wuyishan Nature Reserve in Southeast China to determine the most important stage that affects the regeneration process, seed bank characteristics, seed germination, and seedling growth dynamics were studied in the typical habitats of E. henryi, Phyllostachys pubescens and broad-leaved forests. Results showed that in both P. pubescens and broad-leaved forests, more than 70% of the E. henryi seeds were distributed in moss and litter layers, and few were found in the soil beneath them. However, seed germination in the soil layer was significantly higher than in the moss and litter layers. Seed density, overall seed quality, and germination rate in the broad-leaved forest were significantly higher than in P. pubescens forest. Seed germination was highest in the microsites around the edge of the crown projection area of E. henryi mother trees. The order of survival rate of the seedlings on different ground surfaces was soil > moss > litter. In both habitats, the average seed density was 24.9 seeds m^?2, and the total germination rate was less than 3.5‰. However, seedlings developed from only 1% of the germinated seeds, indicating that the seed germination is the most important stage in the natural regeneration of E. henryi.     

Effects of clump spacing on nutrient distribution and root activity of <Emphasis Type="Italic">Dendrocalamus strictus</Emphasis> in the humid region of Kerala,peninsular India

The humid agroclimatic conditions of Kerala, India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb. (Nees.) is an important one on account of its high growth rate and multiple uses. Stand density, a potential tool in controlling the productivity of woody ecosystems, its effect on growth and root distribution patterns may provide a better understanding of productivity optimization especially when bamboo-based intercropping options are considered. Growth attributes of 7-year-old bamboo (D. strictus) stands managed at variable spacing (4 × 4 m, 6 × 6 m, 8 × 8 m, 10 × 10 m, 12 × 12 m) were studied. Functional root activity among bamboo clumps were also studied using a radio tracer soil injection method in which the radio isotope ³²P was applied to soil at varying depths and lateral distances from the clump. Results indicate that spacing exerts a profound influence on growth of bamboo. Widely spaced bamboo exhibited higher clump diameters and crown widths while clump heights were better under closer spacing. Clump height was 30% lower and DBH 52% higher at the widest spacing (12 × 12 m) compared to the closest spacing (4 × 4 m). With increasing soil depth and lateral distance, root activity decreased significantly. Root activity near the clump base was highest (809 counts per minute, cpm; 50 cm depth and 50 cm lateral distance) at 4 × 4 m. Tracer study further showed wider distribution of root activity with increase in clump spacing. It may be concluded that the intensive foraging zone of bamboo is within a 50-cm radius around the clump irrespective of spacing. N, P and K content in the upper 20 cm was 2197, 21, and 203 kg/ha respectively for the closely spaced bamboo (4 × 4 m) which were significantly higher than corresponding nutrient content at wider spacings. About 50% of N, P and K were present within the 0–20 cm soil layer, which decreased drastically beyond the 20 cm depth. The results suggest that stand management practices through planting density regulation can modify the resource acquisition patterns of D. strictus which in turn can change growth and productivity considerably. Such information on root activities, spatial and temporal strategies of resource sharing will be helpful in deciding the effective nutrition zone for D. strictus. Further, the study throws light on the spatial distribution of non-competitive zones for productivity optimization yields, especially when intercropping practices are considered.     

Influence of umbrella pine (<Emphasis Type="Italic">Pinus</Emphasis><Emphasis Type="Italic">pinea</Emphasis> L.) stand type and tree characteristics on cone production

Most umbrella pine (Pinus pinea L.) stands are managed as agroforestry systems, whose main production is fruit, due to the edible and highly nutritious kernels, and are frequently associated to natural or seeded pastures and grazing. The stands have low density, in order to enhance crown growth and fruit production. Nevertheless, cone production, both with regard to number and weight, varies greatly between stands, trees and years. In this study were selected three agroforestry systems, representative of umbrella pine stands whose main production is fruit, and one stand representative of the timber production system, where fruit is the secondary production. It was evaluated the variability in cone production as a function of the tree’s diameter at breast height and crown diameter and the individual tree’s competition status. The results indicate that stands managed in agroforestry systems with lower competition and individuals with larger diameter at breast height and crown diameter tend to produce more and heavier cones per tree. The first two principal components of the principal component analysis explain 84 % of the variance in cone production, trees’ dimensions and competition index. Tree competition status has a negative impact on production per tree.     

Vitality variation and population structure of a riparian forest in the lower reaches of the Tarim River,NW China

Since 2000, the Chinese government has implemented emergency water diversion measures to restore the damaged riparian forest ecosystem with dominant tree species Euphrat poplar(Populus euphratica Oliv.)at the lower reaches of the Tarim River. In the present study, comparative analysis of variations in the vitality of P. euphratica trees were made using 2005 and 2010 data to illustrate the revitalization process of riparian forest. Poplar trees within 300 m of the riverbed were positively revitalized, while the vitality of trees farther than 300 m from the river decreased. Population structure was studied to demonstrate the development of poplar community. In the first belt, the class structure for the diameter at breast height(DBH) of P. euphratica fit a logistic model, and the 2nd, 3rd and 4th belt curve fittings were close to a Gaussian model; in other plots they were bimodal. Cluster analysis of the composition of the DBH class of poplar trees demonstrated that those within 16–36 cm DBH were the most abundant(58.49% of total) in study area, under 16 cm of DBH were second(31.36%), and trees 40 cm DBH were the least abundant(10.15%). More than 80% of the trees were young and medium-sized, which means that the poplar forest community in the vicinity of the lower Tarim River is at a stable developmental stage. The abundance of juvenile trees of P. euphratica in the first and second measuring belts was 12.13% in 2005 and increased to 25.52% in 2010, which means that the emergency water transfer had a positive impact on the generation of young P. euphratica trees in the vicinity of the river.     

The effect of low-temperature event on the survival and growth of <Emphasis Type="Italic">Juglans mandshurica</Emphasis> seedlings within forest gaps

In forest ecosystems, gap formation changes the allocation of abiotic resources and thus affects the survival and growth of understory plants. However, how tree seedling survival and growth respond to low-temperature events and the influencing mechanisms remain unclear. To clarify how low-temperature event limits the survival and growth of tree seedlings in the montane regions of eastern Liaoning Province, northeast China, we investigated temperature and light intensity within secondary forest gaps, and the survival and growth of Juglans mandshurica seedlings after a low-temperature event in the spring of 2014. Damage to seedlings due to low temperature significantly varied in different aspects. Seedlings in gaps on southeast-facing slopes were the most seriously damaged, followed by those in gaps on northeast-facing slopes. In contrast, seedlings in west-facing gaps and in control plots without slope aspect were not damaged. The freezing injury index for seedlings was negatively correlated with minimum temperature (r = ? 0.608, P < 0.01), but it was positively correlated with light intensity (r = 0.818, P < 0.01). In addition, height and root collar diameter of damaged seedlings were significantly lower than those of the undamaged seedlings (P < 0.01) during the early growing season (April–July), but no significant difference were observed during the late growing season (July–October) (P > 0.05). The extent of seedling damage was directly related to slope aspect. Low temperature and high light intensity were found to be the dominant factors affecting extent of damage to seedlings on southeast- and northeast-facing slopes.     

Identification of ISSR markers linked to flowering traits in a representative sample of <Emphasis Type="Italic">Eucalyptus cladocalyx</Emphasis>

Early flowering and flower abundance have long been considered desirable traits in eucalypt breeding programs. In particular, flowers of Eucalyptus cladocalyx provide a nectar source for the production of honey in arid ecosystems. To identify inter-simple sequence repeat (ISSR) markers that are associated with early flowering and flower abundance in the southern Atacama Desert, we used a sample of 47 trees, representing five Australian provenances of E. cladocalyx. A unified mixed linear model (which considered the effect of genetic structure and the kinship relationship among trees) revealed that three loci were significantly associated with early flowering, which accounted for 10–16 % of the phenotypic variation, while two loci accounted for 11–13 % in flowering intensity. Locus ISO_{1–500 bp} was associated with both flowering traits. This result is consistent with our previous findings indicating that marker-assisted selection on early flowering should have significant and positive impact on flowering intensity. The application of marker-assisted selection to identify trees that flower early and intensively may increase honey production, a resource that generates additional income for the local farmers of the southern Atacama Desert.     

Variation and selection analysis of <Emphasis Type="Italic">Pinus koraiensis</Emphasis> clones in northeast China

Understanding genetic variation is important for efficiently selecting excellent clones and utilizing genetic resources during tree breeding. We investigated 16 growth traits of 50 32-year-old Pinus koraiensis clones. Analyses of variance showed that all the test traits differed significantly among clones. Average height, diameter at breast height (DBH), and volume of all clones were 10.41 m, 21.30 cm, and 0.148 m³, respectively. Phenotypic coefficients of variation and repeatabilities of traits ranged from 4.37 to 48.03% and from 0.013 to 0.900, respectively. There exists significant positive correlations among heights, diameter at different heights (1.3, 3.0, 5.0 m), and volumes; genetic correlation was close to phenotype correlation. Using four growth traits (height, DBH, volume, average crown width) as indices for a comprehensive evaluation, five clones (PK 11, PK 19, PK 04, PK 14, and PK 28), whose traits scored in the top 10%, were selected as elite clones. For these clones, genetic gains in height, DBH, volume and crown height were 8.58, 13.02, 32.72 and 3.83%, respectively. These results provide important information for improving P. koraiensis breeding programs.     

Autoregressive spatial analysis and individual tree modeling as strategies for the management of <Emphasis Type="Italic">Eremanthus erythropappus</Emphasis>

The objectives of this study were to apply statistical techniques to discriminate fertilization treatments of Eremanthus erythropappus (DC.) MacLeish. through autoregressive modeling, and to develop individual tree models for diameter and crown area (CA) projection to define management strategies for candeia plantations subjected to different fertilization treatments. This is an important tree species originating from the Brazilian Atlantic Rain forest and Savannah biomes, intensively used in the cosmetic industry. Nonetheless, to date, research has not addressed the management of natural stands or plantations of the species. Our experiment was located in Baependi, Minas Gerais, Brazil, and comprised of four randomized blocks and 13 treatments. The treatments consisted of 12 different regimes of fertilization plus a control. Each sample plot was composed of 50 plants plus two border plants in a planting spacing of 2.5 × 2.0 m and undergoing pruning at 5 and 6 years of age. Starting in the second year, total tree height (H) and circumference (at 1.30 m from the ground or breast height, CBH) were measured every 6 months. Starting in the fifth year CA was measured. Tree growth varied by fertilization strategy. Differences were detected by using an autoregressive approach, considering that standard statistical methods were not powerful enough to detect significant differences. Three growth groups were formed, and maximum growth was obtained for treatment 10 (NPK, 8-28-16). Management guidelines are provided based on individual tree models for different fertilization levels.     

Population structure and spatial pattern analysis of <Emphasis Type="Italic">Quercus aquifolioides</Emphasis> on Sejila Mountain,Tibet, China

Understanding population structure provides basic ecological data related to species and ecosystems. Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations. Using a 1 ha permanent sample plot data for Q. aquifolioides on Sejila Mountain, Tibet Autonomous Region (Tibet), China, we analyzed the population structure of Q. aquifolioides by combining data for diameter class, static life table and survival curve. Simultaneously, the spatial distribution of Q. aquifolioides was studied using Ripley’s L Function in point pattern analysis. The results showed: (1) Individuals in Q. aquifolioides populations were mainly aggregated in the youngest age classes, that accounted for 94.3% of the individuals; the older age classes had much smaller populations. Although the youngest age classes (Classes I and II) had fewer individuals than Class III, the total number of individuals in classes I and II was also greater than in classes IV to IX. In terms of tree height, few saplings, more medium-sized saplings and few large-sized trees were found. The diameter class structure of Q. aquifolioides populations formed an atypical ‘pyramid’ type; the population was expanding, but growth was limited, tending toward a stable population. (2) Mortality of Q. aquifolioides increased continuously with age; life expectancy decreased over time, and the survivorship curve was close to a Deevey I curve. (3) The spatial distribution pattern of Q. aquifolioides varied widely across different developmental stages. Saplings and medium-sized tree showed aggregated distributions at the scales of 0–33 m and 0–29 m, respectively. The aggregation intensities of saplings and medium-sized trees at small scales were significantly stronger than that of large-sized trees. However, large-sized trees showed a random distribution at most scales. (4) No correlation was observed among saplings, medium- and large-sized trees at small scales, while a significant and negative association was observed as the scale increased. Strong competition was found among saplings, medium- and large-sized trees, while no significant association was observed between medium- and large-sized trees at all scales. Biotic interactions and local ecological characteristics influenced the spatial distribution pattern of Q. aquifolioides populations most strongly.     

Coinoculation of bioinoculants improve <Emphasis Type="Italic">Acacia auriculiformis</Emphasis> seedling growth and quality in a tropical Alfisol soil

We conducted a study to find out if arbuscular mycorrhizal (AM) fungi (Acaulospora scrobiculata, Scutellospora calospora) and phosphate solubilizing bacteria (PSB, Paenibacillus polymyxa) inoculation either individually or in combinations can improve Acacia auriculiformis seedling growth, uptake of nutrients and quality in a phosphorus deficient tropical Alfisol. The seedlings were assessed for various growth and nutrient uptake parameters after 60 days of treatment. Inoculation with P. polymyxa stimulated mycorrhizal formation. Seedling height, stem girth, taproot length, number of leaves and leaf area, plant dry matter production, nodulation, and nodular dry weight were significantly higher for seedlings that were either dual inoculated or triple inoculated compared to individual inoculation of AM fungi or PSB, and uninoculated seedlings. Dual and triple application of AM fungi and PSB also significantly improved the nutrient contents of shoots and roots and nutrient uptake efficiencies. The calculated seedling quality indexes of the AM fungi and PSB inoculated seedling were 25–208% higher than uninoculated seedlings. These findings show that A. auriculiformis seedlings when dual inoculated or triple inoculated performed better than seedlings inoculated with the microbes individually and compared with uninoculated control seedlings. We conclude that bioinoculation is important for the production of high-quality A. auriculiformis seedlings in tree nurseries for planting in nutrient deficient soils.     

Fertility variation in endemic populations of Ehrami black pine (<Emphasis Type="Italic">Pinus nigra</Emphasis> Arnold. subsp. <Emphasis Type="Italic">pallasiana</Emphasis> var. <Emphasis Type="Italic">pyramidata</Emphasis>)

Fertility variation and effective number of parents were estimated in the 100 individuals from each of three plantation populations (P1, P2 and P3) of the endangered Pinus nigra. subsp. pallasiana var. pyramidata established in the Isparta–Golcuk district in southern Turkey in 1990. Potential relations between cone yield and growth characters (height, diameter at breast height, diameter at base and crown diameter) were also investigated. Large differences were found among populations and within populations for cone production and growth characters. Mean cone production was eight (ranging from 6.5 in P2 to 9.1 in P1) for the three populations. The 10 most productive individuals for cones produced 32% of the total cones in P1, 39% in P2 and 34% in P3; 21, 16 and 6 individuals, respectively did not produce any cones in the populations. According to the correlation analyses, the relation between cone yield and growth characters changed for the populations, while height, diameter at breast height and crown diameter were positively significantly correlated (r = 0.182, 0.135 and 0.209; p ≤ 0.05) with cone production for the three populations. Fertility variation was 1.81 in total of three populations, ranging from 1.72 in P3 to 3.45 in P1). Effective number of parents was 142 (55.2 of number of parents censused; 29%, P1; 49.8%, P2; 58.3%, P3).     

Sprouting characteristics of <Emphasis Type="Italic">Quercus pubescens</Emphasis> Willd. and <Emphasis Type="Italic">Quercus frainetto</Emphasis> Ten. trees after a wildfire: To cut or not to cut the burned trees?

The aims of this study were to analyze the sprouting characteristics of Quercus pubescens and Q. frainetto trees after a wildfire and to recommend the appropriate silvicultural treatments in order to achieve dense sprout origin regeneration. This study was carried out in the area that was burned in a wildfire in northeastern Greece. Three years later, 140 Q. pubescens trees and 140 Q. frainetto trees were selected. Seventy trees for each species were individuals that were cut after the fire and were in the form of stumps, while 70 trees were intact top-killed trees, as a result of fire. In each stump and intact tree that was selected, various parameters were measured or counted: the diameter at the level of ground, the number of the developed sprouts (if any) and the height as well as the basal diameter of the tallest sprout, etc. Both species have similar sprouting behavior after a wildfire. Mother tree dimensions positively influenced the number of sprouts and the growth of the tallest sprout per individual. The mean height of the tallest sprout per stump, after three growing seasons from the forest fire, is high in both species (2.08 m for Q. pupescens and 2.29 m for Q. frainetto). Cut stumps had more sprouts than intact trees in both species. Forest practice, in order to maximize the sprouting of Q. pubescens and Q. frainetto trees after a forest fire, should cut the burned trees before the next growing season.