Biomass and net productivity for spruce plantation

SiteandmethodThesiteislocatedintheSuiIingDistrictofHeiIong-jiangProvincefromN47"26'toN48"o6',E127"37'toE128"28'.TheaveragesIopeis15".Themeanelevationis349m.ThemeanannuaItem-peratureis-o.4t.TheaccumuIatedtemperatureof31ooCis1986C-Theamountofprecipitationisfrom6ooto8oomm.Thefrost-freeseasonisabout13od.ThemainsoilisdarkbrownsoiI.The17plots(o.o4hm')fordifferentages,differ-entsitesweremeasured.OnesampletreewasseIectedineverypIot,ThefalIenstemanalysistreesweredividedwithonemeterortwometer…     

Capercaillie habitat, diet and management in a Sitka spruce plantation in central Scotland

The ancestral habitat of capercaillie in most of its range isScots pine forest with an understorey of blaeberry. Keillourforest in Perthshire is dominated by Sitka spruce, has littleblaeberry, yet had a high density of capercaillie. Food andhabitat use by capercaillie were studied there from 1991 to1994. Seven cocks and two hens were caught, and marked withsmall radio transmitters. The habitats they occupied and foodremains in their droppings provided information on home range,habitat utilization and diet through the year. Sitka sprucewas the main food in autumn, winter and spring but was equalledby the fruiting heads of sedge in summer. Larch was the secondmost abundant item in spring and autumn diets. Sedge was plentifulon the wet restocks associated with the gleyed soils at Keillourand may provide a partial substitute for blaeberry in summer.Capercaillie showed a clear preference for the oldest blocksof trees, especially in winter. Sitka spruce, Norway spruceand Scots pine were used roughly in proportion to their availabilityin the birds' home range, but larch stands were used more thanexpected from availability. In summer, all birds used restocksto some extent. Management recommendations to encourage capercailliein commercial plantations largely comprising exotics are thatmature stands over 45 years and well-vegetated restocks shouldeach occupy at least 20 per cent of the forest, larch and blocksof mixed conifers each at least 15 per cent of the ground. Blaeberryshould be encouraged and, if possible, patches of windthrowinvolving living trees with the main root intact should be retained.     

粗枝云杉人工林产区区划研究

通过逐步回归分析表明,影响粗枝云杉人工幼林生产力的主导气象因子是年平均温度,林分生产力与 年平均温度呈正相关。按林分生产力的差异显著性,将四川省粗枝云杉人工林划分为三个产区,其生产力大小排序为Ⅰ类＞Ⅱ类＞Ⅲ类,粗枝云杉中心分布区并不一定是中心产区。     

Understanding plantation transformation using a size-structured spatial population model

Plantation transformation is a goal of increasing interest to silviculturalists. The target forest state is characterised by high variance in age and size, and an irregular spatial structure, which leads to inhomogeneous interactions between, and consequent development of, trees in the stand. This presents a difficulty for traditional methods such as yield tables, and demands a more careful consideration of stand dynamics. On the other hand, while forestry has a great heritage of simulation, the level of complexity implemented at an individual level generally precludes direct understanding of stand scale behaviours, and leads to difficulties in verification with appropriate data.A promising approach is the application of relatively simple models developed by ecologists. These can be adapted to yield accurate representations of forest stands, while being highly amenable to analysis. Motivated by data from Scots pine (Pinus sylvestris L.) stands, we here apply a simple spatial birth-death-growth model to the comparison and analysis of transformation strategies for plantation stands. The model captures the effects of neighbours in a way which retains the conceptual simplicity of a generic, analytically solvable model, while allowing insights into the driving factors of population dynamics.Timing and intensity of management interventions, as opposed to their specific criteria, are of primary importance: thinnings of a moderate intensity performed over a long period produced the best results. Variation in the strategy applied leads to more subtle effects which transformation strategies must also take into account, such as the development of variation in size of the remaining trees (increased using spatially correlated thinnings), the survival chances of regeneration and “underplanted” trees, and the overall productivity of the stand (increased using spatially homogeneous crown thinning). Finally, we demonstrate the robustness of model predictions to fundamental choices of model formulation.     

Spatiotemporal distribution of aboveground litter in a Cryptomeria japonica plantation

We assessed the vertical distribution of litter and its seasonal patterns in the canopy and on the forest floor (soil), as well as litterfall (the flux of litter from the canopy to the soil) in a 33-year-old plantation of Japanese cedar (Cryptomeria japonica D. Don). The masses of total litter, dead leaves, and dead branches in the canopy of C. japonica trees averaged 34.09, 19.53, and 14.56 t dry wt ha⁻¹, respectively, and were almost constant during the study period. The total masses of the annual litterfall were 4.17 and 5.88 t dry wt ha⁻¹ year⁻¹ in the two consecutive years of the study. The mass of the soil litter averaged 7.95 t dry wt ha⁻¹ during the same period. All relationships between the mass of canopy litter and tree-size parameters (diameters at breast height and at the lowest living branch) were linear in a log-linear regression. Compared with the results for this plantation at a younger stage (16 years old), our results suggest that the total mass of dead leaves attached to each tree increases markedly with increasing age, but that the trajectory of this increase as a function of tree size may change from an exponential to a saturation curve with increasing stand age.     

Quantifying height growth and monthly growing degree days relationship of plantation Taiwan spruce

The future of the endemic Taiwan spruce (Picea morrisonicola) under climate change is of great concern. It is the southernmost species of the genus and its current distribution is limited to high altitudes of Taiwan. As a first step toward assessing the impact of future temperature changes on the species, we quantified the effects of past monthly growing degree days (GDD) on the height growth of plantation Taiwan spruce based on nonlinear mixed-effects growth analysis. Our results showed that past GDD variations had both positive and negative effects on the height growth of the species. July of the preceding year had the greatest influence on current year height growth. An increase in the mean GDD level of the current May would also promote height growth. In contrast, a warmer previous November or current January had negative effects on height growth. If the established height growth–GDD relationship holds, the influences of climate change on Taiwan spruce height growth will depend on the timing of the temperature increases, as well as on the trees current growth stages. Our results suggested that a warmer climate would have a greater influence on trees that are still in the early stages along the height growth trajectory. The established height growth–GDD relationship will be a keystone for developing models assessing how Taiwan spruce responds to climate change.     

桤木生物量及根系分布规律

采用全部、分层挖取法,研究洞庭湖区9年生桤木人工林的生物量及根系分布规律。结果表明：桤木单株生物量为44.39ks／株,各器官生物量大小排序为树干〉树根〉树枝〉树皮〉树叶;林分总生物量为96.06/hm^2;林分净生产力为10.67/（hm^2·年）。桤木根系发达,根深60～80cm;根系中以根桩和粗根的生物量所占的比例最大,两者之和占根系总生物量的84.27％。在垂直分布上,根系主要分布在0～40cm的土层中,其生物量占根系总生物量的84.51％。在水平分布上,根系主要分布在离树桩0～50cm的范围内,其生物量占根系总生物量的84.49％;特别是粗根,其生物量占根系总生物量的29.47％;茵根的生物量占根系总生物量的0.39％,主要分布在离树桩50～100cm的范围内,该区域根系的生物量占茵根总生物量的70.97％。     

13C and 15N isotopic fractionation in trees, soils and fungi in a natural forest stand and a Norway spruce plantation

¹⁵N and ¹³C natural abundances of foliage, branches, trunks, litter, soil, fungal sporophores, mycorrhizas and mycelium were determined in two forest stands, a natural forest and a Norway spruce plantation, to obtain some insights into the role of the functional diversity of saprotrophic and ectomycorrhizal fungi in carbon and nitrogen cycles. Almost all saprotrophic fungi sporophores were enriched in ¹³C relative to their substrate. In contrast, they exhibited no or very little shift of δ¹⁵N. Judging from the amount of C discrimination, ectomycorrhizal fungi seem to acquire carbon from their host or from dead organic matter. Some ectomycorrhizal species seem able to acquire nitrogen from dead organic matter and could be able to transfer it to their host without nitrogen fractionation, while others supply their host with ¹⁵N-depleted nitrogen. Moreover ectomycorrhizal species displayed a significant N fractionation during sporophore differentiation, while saprotrophic fungi did not.     

Temporal variation and high-resolution spatial heterogeneity in soil CO2 efflux in a short-rotation tree plantation

Soil CO2 efflux (SR) is the second largest carbon flux on earth. We investigated the driving factors of the seasonal change and short-distance spatial variation in SR in a short-rotation plantation of willow (Salix viminalis Orm). Total annual SR ranged from 723 to 1149 g Cm(-2) year(-1). Both an exponential and a logistic model were fitted to the data, with soil temperature at a depth of 5 cm as the independent variable. The R2 values for individual sampling points ranged from 0.83 to 0.95 and from 0.85 to 0.93 for the exponential and logistic models, respectively, indicating that soil temperature largely determined the seasonal variation in SR. Modeled soil SR at 10 degrees C ranged from 1.22 to 1.95 micromol m(-2) s(-1), whereas modeled annual Q(10) values were between 3.31 and 6.13. These high Q(10) values were attributed to the absence of drought during the study in 2005. When the coefficients of the general SR models were replaced by linear dependencies on soil and vegetation-related characteristics, the resulting spatially explicit exponential and logistic SR models explained 85 and 86%, respectively, of the variability within the dataset. The analysis indicated that soil carbon concentration, leaf area index, soil pH and root biomass caused differences in SR at the short distances considered in this study. However, incorporating information on variables considered to account for spatial variability in the model did not result in a higher R2 compared with a simple temperature function. When the general SR models were applied to independent datasets from the same plantation, the logistic model provided a better fit than the exponential model when drought occurred. Drought greatly reduced the annual Q(10) values of SR.     

The effect of thinning on ground spider diversity and microenvironmental factors of a subtropical spruce plantation forest in East Asia

Currently, information about the effect of forest management on biodiversity of subtropical plantation forests in Asia is quite limited. In this study, we compared the spider community structures and guild compositions of subtropical Cryptomeria japonica plantation forests receiving different degree of thinning (0, 25 and 50 %) in central Taiwan. The ground spider diversities and environmental variables were sampled/measured once every 3 months for 1 year before thinning and 2 years after thinning. Results showed that before thinning spider compositions did not differ significantly among three plantation forest types. Two years after thinning, spider species and family compositions of three plantation forest types differed significantly. In all three plantation forest types, the spider composition differed from year to year, indicating existence of temporal variations in spider diversity. Ground hunters (increased 200–600 % in thinned forests), sheet web weavers (increased 50–300 % in thinned forests) and space web weavers (decreased 30–50 % in thinned forests) were the major contributors of the observed spider composition differences among plantation forests receiving different treatments. The stands receiving thinning treatments also had higher illumination, litter decomposition rate, temperature and understory vegetation density. Thinning treatments might have changed the structures of understory vegetation and canopy cover and consequently resulted in abundance and diversity changes of these guilds. Moreover, the heterogeneity in understory vegetation recovery rate and temporal variation of spider composition might further generate spider diversity variations in subtropical forests receiving different degree of thinning.     

Effects of thinning on plant species diversity and composition of understory herbs in a larch plantation

The effects of thinning on plant species diversity and composition of understory herbs in a larch plantation were investigated. The relationships between plant species diversity and composition of understory herbs and light conditions were established. Twenty-five 1 m × 1 m plots and fifteen 13 m × 1 m transects were set up in unthinned and thinned stands, respectively. All the transects in the thinned stands were set across the thinned rows and unthinned rows, and each of them was divided into nine 1 m × 1 m sub-plots. The herb diversity and light conditions were observed in each plot and sub-plot. The results show that there was a significant difference in herb diversity between the thinned and unthinned stands. All biodiversity indices except for evenness index in the thinned stand were higher than those of the unthinned stand, i.e., the herb diversity increased after thinning. According to the changes in herb densities and whether one species could be found in a stand or not before and after thinning, all herb species were classed into three types: positive, neutral and negative species, which referred to a species newly appeared and having an obviously increased density after thinning, with no obvious changes in its appearance and density after thinning, and disappeared and having an obviously decreased density after thinning, respectively. Many new species were found in the thinned stand like Corydalis pallida, Prenanthes tatarinowii, Vicia unijuga and Sonchus brachyotus etc. However, most species found in both the thinned and unthinned stands were negative species. In all nine subplots, only 11 and 10 species were found in spring and in autumn respectively, accounting for 17.74% and 15.15% of all the species in the thinned stand, respectively. All biodiversity indices were the highest in the center sub-plots and most of them tended to reduce from middle to side sub-plots. There was a close correlation between most of the three types of species and light conditions which was similar to each other in the thinned and unthinned stands. __________ Translated from Chinese Journal of Ecology, 2006, 25(10): 1201–1207 [译自: 生态学杂志]     

Variation in the relative abundance of the large pine weevil among Sitka spruce plantation sites

Between 1993 and 1994 over 160 forest sites were sampled toobtain indices of pine weevil (Hylobius abietisL.) densities.Overall 48 variables were tested for their ability to explainvariation in weevil numbers between compartments. The modelsgenerated from the sample data identified 14 variables as significantin influencing weevil densities. In this research note the variablesare identified, and their relationship to forest managementdiscussed     

Floristic analysis and distribution pattern of alien plants in Shandong Province, eastern China

Alien plants, along with their ecological invasion and negative impacts on indigenous species diversity and ecosystems, are one of the major topics of current ecological research. The background investigation and floristic analysis of alien plants are very important and form an essential database for invasive species research, control and management. In our study these alien plants, mainly collected from the Flora of Shandong Province, combined with a field survey, were studied and analyzed. We also established a floristic database. Our findings are as follows: 1) there are a total of 827 alien species, belonging to 122 families and 416 genera of which 348 species were imported from other countries; 2) a high proportion, 39.0% of the flora in Shandong Province, is accounted for by alien species, of which 21 dominant families largely belong to the Rosaceae, Leguminosae, Asteraceae and Gramineae; 3) the diverse geographical distribution of the genera is characterized by species dominant in the temperate zone which accounts for 52.5% of the alien plants and 44.1% of the plants from the tropics; 4) the origins of alien species and their centralized distribution in Shandong together show the anthropogenic effect and unnatural impacts on the environment and 5) in Shandong Province, alien plants originate more from temperate zones than from any other areas of the world. __________ Translated from Chinese Journal of Ecology, 2007, 26(4): 489–494 [译自: 生态学杂志]     

更新采伐对华北落叶松人工林空间格局的影响

种群空间分布格局是种群个体在水平空间的分布方式,对林分空间格局的研究和分析可以为林业生产提供宝贵资料和实践指导,同时科学地制定抚育经营措施是提高森林质量的关键环节。本试验研究了更新采伐对华北落叶松人工林种群空间分布格局的影响。结果表明,华北落叶松种群的格局强度随研究尺度的不同而不同。通过更新采伐使得原先呈聚集分布的种群空间格局变为随机分布或者使得其聚集强度明显降低。因此在华北落叶松种群生长的整个过程中应定期进行更新采伐,伐除林分中生长落后的林木和有害木,降低林分密度,改善林分结构,保证林分朝着健康稳定的方向发展,实现林分的可持续经营。     

Floristic composition and structure of the Kibate Forest along environmental gradients in Wonchi,Southwestern Ethiopia

Dry evergreen montane forests in Ethiopia are severely threatened.The status of species composition and structure of forest vegetation are important indicators ...     

灰木莲人工林营养元素分配及其积累特征

对南宁市46年生灰木莲人工林的9种营养元素(N、P、K、Ca、Mg、Fe、Mn、Zn和Cu)的含量、积累量、年净积累量及其分配特征进行了研究。结果表明:灰木莲不同组分的营养元素含量大致为树叶>树皮>树根>树枝>干材。大量元素N、K在树根中的含量最高,P、Mg在树叶中的含量最高,而Ca则在树皮中含量最高;微量元素在各组分中的含量则以Mn最高,Fe、Zn次之,Cu最低。灰木莲人工林营养元素积累总量为1 948.78 kg/hm2,其中乔木层的营养元素积累量为1 715.22 kg/hm2,占林分营养元素积累总量的88.02%;草本层为74.33 kg/hm2,占总积累量的3.81%;灌木层为83.19 kg/hm2,占总积累量的4.26%;凋落物层为76.04 kg/hm2,占总积累量的3.90%。灰木莲人工林营养元素年净积累量为37.32 kg/(hm2·a),各组分营养元素年净积累量排列顺序为干材>树根>树皮>树叶>树枝。     

兴安落叶松人工林地表可燃物分布研究

以大兴安岭南部兴安落叶松林人工林为研究对象,根据立地因子(海拔、坡度、坡向)和林分特征(郁闭度、密度、平均树高、平均胸径等)设置标准地,利用收获法调查地表可燃物负荷量,包括每个样方内的灌木和草本1h时滞、10h时滞和100h时滞负荷量。据此,通过相关性分析研究立地、林分因子对可燃物负荷量分布的影响。     

间伐对杉木人工林生态系统碳贮量及其空间分配格局的影响

对间伐5年后的湖南会同杉木人工林生态系统碳贮量及其空间分配格局进行了研究。结果表明:(1)无论是间伐区还是对照区,单株杉木各器官的碳贮量以及乔木层各组分的碳贮量均与其生物量成正比,且均以树干的碳贮量最高,分别占单株杉木碳贮量和乔木层碳贮量的65.63%和64.99%以上,但间伐区单株杉木各器官碳贮量和乔木层各组分碳贮量的大小排序均与对照区有所不同。(2)间伐后,单株杉木的碳贮量增加了48.96 kg,增长了62.91%;但乔木层碳贮量下降了17.37%,减少了15.56 t.hm-2;林下植被碳贮量增加了1 399.42 kg.hm-2,增长了230.94%;杉木林生态系统的碳贮量减少了20.824 t.hm-2,下降了11.73%;其中植被层碳贮量减少了14.162t.hm-2,下降了15.70%,土壤层减少了8.61 t.hm-2,下降了10.09%,死地被物层增加了1.948 t.hm-2,增长了93.34%,且杉木林生态系统中碳贮量的空间分布格局发生了一定的变化。表明间伐可导致杉木人工林生态系统各组成部分的碳贮量及其空间分布格局发生不同的变化。