Growth responses of six seed sources of Pinus brutia Ten. (Turkish red pine) to herbaceous weed competition

Herbaceous weeds present amajor obstacle to foresters in the earlyestablishment and growth of Turkish red pine (Pinus brutia Ten.), an important coniferof the semi-arid Mediterranean region. Greatgenetic variability of this pine species indrought resistance has already beenwell-studied. The existence of such variationwithin this species in relation to herbaceousweed competition is unknown. This studyinvestigated the effect of herbaceous weedcompetition on the growth of the seedlings ofTurkish red pine seed sources with differentmoisture regimes in their native sites, usingthe rapid screening technique. Two-month-oldTurkish red pine seedlings were grown inindividual pots in a glasshouse either with orwithout joint goose goat grass (Aegilopscylindrica L.). After two simulatedgrowing seasons, grass competitionsignificantly and progressively reduced pinegrowth. Although mean total pine biomass wasreduced by 71% due to weed competition,seedlings of different pine seed sourcesdisplayed significant differences in growthresponses to the weed treatments: dry site seedsource seedlings generally exhibitedsignificantly greater growth than moist siteseed source seedlings under weed competition. These results suggest that competition fromherbaceous weeds is an important factor inreducing the early growth of Turkish red pineseedlings, and that selection ofcompetition-tolerant seed sources can result insubstantial enhancement of the competitivestatus of this pine species against itsherbaceous competitors in early years.     

Micropropagation of mature Calabrian pine (Pinus brutia Ten.) from fascicular buds

Dormant meristems of fascicles explanted from 10-year-old, field-grown trees of Pinus brutia Ten. were cultured in vitro. Browning of cultured fascicles was reduced by including 150 mg l(-1) sodium diethyldithiocarbamate (SDD) in a cytokinin-containing medium. The stage of development of fascicles when placed in culture affected both shoot-bud production and the degree of browning. Only fascicles at an advanced stage of development had a high rate of shoot-bud production. Fascicles cultured for 6 weeks in initiation medium containing 150 mg l(-1) SDD and then for 4 weeks in initiation medium containing 1 mg l(-1) insoluble polyvinylpolypyrrolidone showed the highest rate (23%) of shoot-bud development and the lowest rate (15%) of browning. Elongation of activated shoot buds was considerably enhanced by reducing the concentration of cytokinin in the culture medium. Only shoots >/= 20 mm in height were capable of producing further crops of buds and shoots. When treated with a combination of auxin and cytokinin, only 16% of the elongated shoots produced roots.     

Deadwood volume assessment in Calabrian pine (Pinus brutia Ten.) peri-urban forests: Comparison between two sampling methods

In the Sustainable Forest Management, deadwood is a fundamental substrate for numerous species, and a key factor in carbon and nutrient cycles. The main aim of the paper is to estimate the amount of deadwood in two Calabrian pine forests (Monte Morello in Italy; Xanthi in Greece) characterized by different stand conditions and management practices. The second aim is to compare two different sampling methods to estimate the volume of lying deadwood: the fixed-area sampling (FAS) method and the line intersect sampling (LIS) method. The results show that the Monte Morello peri-urban forest is characterized by a high quantity of deadwood (75.1 m³ ha^?1) divided in 80% of lying deadwood, 18% of standing dead trees, and 2% of stumps. The Xanthi peri-urban forest is characterized by a total amount of deadwood of 9.21 m³ ha^?1 divided in 34% of lying deadwood, 18% of standing dead trees and 48% of stumps. The mean volume of lying deadwood in Monte Morello estimated using the FAS is 59.91 m³ ha^?1, while using the LIS the mean volume is 64.9 m³ ha^?1. In the Xanthi, the mean volume of lying deadwood is 3.11 m³ ha^?1 using FAS and 5.49 m³ ha^?1 using LIS.     

Morphological and physiological responses to drought stress of European provenances of Scots pine

Increased frequency and intensity of drought episodes as a consequence of current and predicted climatic changes require an understanding of the intra-specific variability in structural and physiological characteristics of forest trees. Adaptive plasticity and genotypic variability are considered two of the main processes by which trees can either be selected or can acclimate to changing conditions. We tested for the relative importance of genotypic variability, phenotypic plasticity and their interaction by comparing the growth and physiological performance of 15 provenances of Scots pine (Pinus sylvestris L.), under two contrasting irrigation regimes. Selected provenances representing the distribution range of the species in Anatolia, Turkey, were contrasted with seed sources spanning the range from Spain to the UK, in Europe. We found a strong latitudinal differentiation among the 15 provenances for survival after drought, largely the result of the higher mortality of some western and central European provenances. Differentiation in diameter and height growth was also clear with the worst provenance coming from Western Europe (UK). Among the Turkish provenances, the more extreme southern high-elevation populations showed greater survival and lower growth rates overall. Differences in growth and survival were related to differences in photosynthetic pigment and nutrient contents and in the photosynthetic efficiency of photosystem II. Plasticity was strongest for growth characters and pigment contents.     

Variation in growth and osmotic regulation of roots of water-stressed maritime pine (Pinus pinaster Ait.) provenances

Hydroponically cultivated Pinus pinaster Ait. seedlings of a drought-sensitive population from France (Landes) and of a more drought-adapted population from Morocco (Tamjoute) were subjected to a progressive increase in water stress by additions of an osmoticum (polyethylene glycol 600) to the nutrient solution. The final osmotic potential (Psi(ms)) of the nutrient solution was achieved over a period of up to 6 days, and ranged from -0.03 (control, no added osmoticum) to -0.8 MPa. In the 6 days during which water stress was imposed, roots elongated faster in the Moroccan provenance than in the French provenance, but the applied water deficits did not inhibit root elongation in either population. Among treatments, root dry weight per unit root length, total root dry weight and root/shoot dry weight ratio increased with decreasing Psi(ms) in both provenances. Both the water potential (Psi(w)) of the roots (apices) and the water potential difference between the roots and the nutrient solution decreased as Psi(ms) decreased. The reduction in Psi(w) was matched by a decrease of comparable magnitude in cell osmotic potential (Psi(pi)) so that root turgor was unaffected by the Psi(ms). Osmotic adjustment was greater, however, in the Moroccan provenance than in the French provenance. Consequently, under the osmotically imposed water stress, the water potential difference between root and nutrient solution was greater in the Moroccan provenance than in the French provenance. Similar changes in plant water relations were observed when seedlings were grown in drying sand.     

Differences in physiological and biochemical responses to summer drought of Pinus nigra subsp. pallasiana and Pinus brutia in a natural mixed stand

Understanding how tree species respond to drought in their natural environment is needed to predict forest adaptation and management practices under global environmental changes. This study was carried out to determine and compare physiological and biochemical responses to variations in environmental conditions during summer drought of mixed natural stands of Pinus nigra Arn. subsp. pallasiana(Lamb.) Holmboe and Pinus brutia Ten. Midday xylem water potential(■), water relations,photosynthetic pigments, total soluble sugar and proline contents were investigated during the growing season. ■ followed a similar seasonal trend in both species but P.nigra subsp. pallasiana had higher ■ than P. brutia. The ■ gradually decreased from June, reached its lowest value in August, and then increased again. Gradual decreases in the osmotic potential at turgor loss point(■) were observed during the summer. Generally,■ was lower in P. brutia. Total soluble sugars decreased from April to June for P. brutia, then increased and stayed relatively constant August to October. Similar changes were found at lower values in P. nigra subsp.pallasiana. Prolin accumulation and photosynthetic pigments were higher in P. brutia. The results indicate that physiological and biochemical responses of both species against changing environmental conditions were in different degrees but followed similar trends. P. nigra subsp.pallasiana is more sensitive to summer drought than P.brutia in their natural environment.     

Growth and visible responses of Scots pine (Pinus sylvestris L.) seedlings to simulated summer frost

Scots pine seedlings, 20–30 days old, were exposed to simulated summer frost in controlled environment growth chambers. The responses observed showed extreme variation between individual seedlings; seedlings suffering from needle-necrosis, healthy-looking, and dead seedlings were found in the same treatment. Four days exposure to temperatures below –4.5°C caused multiple-leaders maximally in 7.7 % of the pine seedlings and resulted in decreased shoot and root dry weight and shoot length.     

Photosynthetic acclimation of shade-grown red pine (Pinus resinosa Ait.) seedlings to a high light environment

Photosynthetic light acclimation in red pine (Pinus resinosa Ait.) seedlings was examined in a greenhouse study to better understand the physiological response of this species to increased light intensity following release from competition. Seedlings grown in a high (HL), medium (ML) or low (LL) light environment for 12 weeks were transferred to high light. Gas exchange and chlorophyll fluorescence of ML and LL seedlings were measured prior to and following transfer and compared with the HL control treatment. Photosynthetic characteristics were related to initial light treatment and time after transfer. Acclimation of gas exchange features to high light in shade formed ML and LL foliage was relatively rapid, with similar values among light treatments within 57 days of transfer. Acclimation of net photosynthetic rate was similar in ML and LL seedlings, and was associated primarily with increased mesophyll conductance to CO₂. The ratio of variable to maximal chlorophyll fluorescence (F_v/F_m) decreased initially after transfer, especially in LL seedlings, but recovered to normal values after 57 days. Red pine seedlings appear to be well adapted for photosynthetic acclimation to high light intensity, consistent with that reported for other early successional tree species.     

The effects of thinning treatments on density, MOE, MOR and maximum crushing strength of Pinus brutia Ten. wood

The purpose of this study was to determine the effects of plantation thinning on various wood properties of Pinus brutia Ten. Tree samples were obtained from heavily and moderately thinned and unthinned 33–35 year-old plantations. Wood properties were examined in various wood zones including 16 annual rings after the first treatment. The results of this study showed that there was a significant relationship between thinning intensity and radial increment (1.30 m) for an individual tree. Thinning treatments increased annual ring width especially a few years after thinning. Heavy thinning treatments were especially effective in impacting mean ring width values at breast height. However, the percentage of late wood did not differ much between the samples. Based on the results of correlation analysis between ring width and late wood percentage there was no significant correlation identified. Mean wood density was not affected by the treatments. Also, no significant correlation was found between thinning and examined strength properties (MOR, MOE and compression strength parallel to grain). However, a relationship was found between wood density and all strength properties except for MOE. The current results suggest that thinning can produce improvements in ring width without any negative impacts on investigated wood properties. It is recommended that subsequent studies should be designed to understand genetic effects and maximize treatment effects.     

Loblolly pine (Pinus taeda L.) essential oil yields affected by environmental and physiological changes

ABSTRACT

Loblolly pine (Pinus taeda L.) is one of the most abundant timber species in the United States and needles from this species contain essential oils (EOs) with antibacterial properties. Needles from trees of one loblolly pine clone were assayed for the EOs α-pinene, β-pinene, terpineol, limonene, and caryophyllene across a growing season. Results showed strong positive correlations among EOs, except for caryophyllene, with Pearson’s correlation values ranging from .66–.96. Simultaneously, physiological attributes of tree stomatal conductance, water stress, and environmental attributes including soil moisture, photosynthetic active radiation (PAR), temperature, wind speed, and relative humidity were measured. The plants modulated the EO concentrations as a function of a changing environment season. The collection month had the largest effect on EO yields and highest yields were during the beginning of the growing season. Decreases in EOs were evident as the growing season progressed and as plants exhibited greater water stress, temperatures, solar radiation, and less stomatal conductance and soil moisture. Loblolly pine’s main constituents of EOs were tightly linked and were influenced by seasonal changes (i.e., month); still, environmental/physiological attributes exhibited significant effects on α-pinene, β-pinene, and limonene concentrations. Early spring conditions with ample water were most conducive to high concentrations of EOs.     

Development of ecoregion-based merchantable volume systems for Pinus brutia Ten. and Pinus nigra Arnold. in southern Turkey

Estimating individual tree volume is one of the essential building blocks in forest growth and yield models.Ecologically based taper equations provide accurate volume predictions and allow classification by merchantable sizes, assisting in sustainable forest management.In the present study, ecoregion-based compatible volume systems for brutian pine and black pine in the three ecoregions of southern Turkey were developed. Several well-known taper functions were evaluated. A secondorder continuous-time autoregressive error structure was used to correct the inherent autocorrelation in the hierarchical data, allowing the model to be applied to irregularly spaced and unbalanced data. The compatible segmented model of Fang et al.(For Sci 46:1–12, 2000) best described the experimental data. It is therefore recommended for estimating diameter at a specific height, height to a specific diameter, merchantable volume, and total volume for the three ecoregions and two species analyzed. The nonlinearextra sum of squares method indicated differences in ecoregion and tree-specific taper functions. A different taper function should therefore be used for each pine species and ecoregion in southern Turkey. Using ecoregionspecific taper equations allows making more robust estimations and, therefore, will enhance the accuracy of diameter at different heights and volume predictions.     

Stand structure and dynamics of four native Scots pine (Pinus sylvestris L.) woodlands in northern Scotland

Stands in four native pinewoods (Glenmore, Black Wood of Rannoch,Glen Garry and Glen Affric) dominated by Scots pine (Pinus sylvestrisL.) with contrasting management histories and climates wereassessed for differences in age, structure and dynamics. Treeage, height, diameter at breast height (d.b.h.), basal area,stem density and x, y coordinates were used to compare the recruitmentof trees (>1.3 m height, >7 cm d.b.h.), saplings (>1.3m height, <7 cm d.b.h.) and seedlings (<1.3 m) followingdisturbance events and protection from browsing. There was a20-year lag between localized intensive cultivation and treerecruitment on sites that were protected from deer browsing(Glenmore and Glen Garry). Recruitment was low in sites withdisturbance but no protection (Black Wood of Rannoch). The oldestpopulation, Glen Affric, showed signs of initial intense recruitmentfollowed by a long period of nil recruitment. Abundant standingdead trees were recorded only in Glen Affric, and prolific birchand rowan only in Glen Garry. Managers should consider localizedintense cultivation in conjunction with a complete reductionin browsing pressure for rapid seedling recruitment and increasedstructural diversity.     

Short-day treatment affects growth,physiological parameters and needle proteome of Chinese pine (Pinus tabuliformis Carr.) seedlings

New Forests - Previous studies have proven that short-day treatment is an effective means to regulate shoot growth and abiotic stress resistance in conifers. However, the effects on Chinese pine...     

Altitudinal and longitudinal variations in Pinus brutia (Ten.) of Crete Island,Greece: some needle,cone and seed traits under natural habitats

Four populations representing the entire natural distribution range of Pinus brutia (Ten.) in Crete (Greece) were sampled to determine: (1) Altitudinal variation within populations of Lassithi, Vorizia, Koustagerako, and Samaria, and; (2) Longitudinal variation among the four populations, based on morphological and anatomical differences in cone, needle and seed characteristics. Samples were collected from 10 trees per altitude, at three altitudes in each population. A total of 12 morphological and anatomical traits from needles, cones and seeds were analyzed to assess the altitudinal and longitudinal variations of the species in the island. The number of teeth per cm showed significant (P<0.01) differences between altitudes in Samaria, Vorizia and Lassithi, while needle length, width and the number of resin canals showed significant differences (P<0.01) between altitudes in Koustagerako. Cone width showed patterns of variation along the altitudinal gradient in Koustagerako, Samaria and Vorizia. Most traits had their highest means at the middle altitudes (650masl) in all the four populations. Overall, no clear altitudinal differentiation was detected, probably due to high rate of gene flow. Longitudinal variability showed a clear pattern of differentiation along the east–west climatic gradient. Needle length, width, sheath length, number of teeth per cm and the number of resin canals were the most useful traits for determining the climatic gradient clines.     

Osmotic adjustment in three-year-old seedlings of five provenances of maritime pine (Pinus pinaster) in response to drought

Three-year-old seedlings of five provenances of Pinus pinaster Ait. that differed in climatic conditions at their geographical origin were subjected to decreasing soil water availability. The degree of needle osmotic adjustment (OA) was estimated based on logarithmic plots of needle relative water content (RWC) against needle osmotic potential (Psi(pi)); i.e., lnRWC versus -ln(-Psi(pi)). There were significant differences among provenances in active OA (0.13 to 0.30 MPa for a decrease in RWC to 80%), and a clear negative relationship was found between OA and precipitation (650 to 1280 mm of mean annual rainfall) at the geographical origins of the provenances. A high osmoregulatory capacity contributes to the maintainance of positive turgor at low water potentials. We conclude that OA is one of the mechanisms underlying adaptation to drought in P. pinaster. Solute accumulation was about 2.3 times higher in the provenance from the driest site than in the provenance from the wettest site. The contribution of osmotic adjustment to differences in drought tolerance mechanisms among provenances is discussed.     

The temperature and length for the release of primary and induction of secondary physiological dormancy in Korean pine (Pinus koraiensis Sieb. et Zucc.) seeds

New Forests - Primary physiological dormancy and secondary physiological dormancy of Korean pine seeds restrict the regeneration of broad-leaved Korean pine (Pinus koraiensis) mixed forest. Dry and...     

Microstructural investigation of UV-laser irradiated pine (Pinus silvestris L.)

Summary Different surfaces of pre-sanded pine (Pinus silvestris L.), namely radial surfaces, tangential surfaces and cross sections, have been subjected to microstructure examination. UV-laser irradiation with a wavelength of 248 nm and an energy of 350 mJ is used to enhance the microstructure exposure. It has been shown that UV-laser irradiation is a useful and practical method for revealing microstructural details. This is more pronounced on the cross section. Sanding with emery paper finer than 800 mesh can reveal microstructure on the radial surface equivalent to that revealed by UV-laser irradiation. On the radial and tangential surfaces, more earlywood is extracted after UV-laser irradiation, resulting in an uneven surface. Some features such as loose fibres and a rack-gearing-like structure on the radial and tangential surfaces, as well as a loss of radially oriented cell walls on the cross section are observed as a result of the UV-laser treatment. The rack-gearing structure is composed mainly of a sawtooth-like pattern. The length of the sawtooth is in most cases approximately 9 and 19 m.This work was carried out in the Department of Wood Technology and Processing, Royal Institute of Technology (KTH). Financial support from KTH is gratefully acknowledged.     

Susceptibility of cones and seeds to fungal infection in a pine (Pinus spp.) collection

Summary Thirty‐one fungi, members of Ascomycota and Deuteromycota, were isolated from cones/seeds of 28 hosts (Pinus spp.) originating from East Asia, Europe and North America, and growing at the Montreal Botanical Garden, Canada. A total of 21 taxa of these isolated fungi are considered pathogens. The damage severity was most prevalent on Diploxylon pines of European provenance (Pinus nigra, Pinus mugo and Pinus sylvestris), and one indigenous North American species (Pinus albicaulis). Twelve fungi occurred on different hosts, i.e. Sphaeropsis sapinea (12), Herpotrichia juniperi (8), Truncatella hartigii (7), Ceuthospora sp. (5), Fusarium, spp. (5), Pestalotiopsis funerea (3), Phomopsis sp. (3), Valsa spp. (anamorph. Cytospora) (3), Diaporthe sp. (3), Fusicoccum sp. (2) and Sirococcus strobilinus (2). Sphaeropsis sapinea, Herpotrichia juniperi, Phomopsis conorum, Truncatella hartigii, Tubercularia sp. and Valsa spp. were related to high cone and seed damage. For the most frequently observed Sphaeropsis sapinea damage, the subgenus Haploxylon was less susceptible than Diploxylon, and P. sylvestris less than P. nigra and P. mugo. Pinus resinosa showed more tolerance to S. sapinea. Truncatella hartigii was more frequently associated with necrotic lesions on cones/seeds in comparison with Pestalotiopsis funerea. The results are discussed in the context of arboretum, seed orchard, nursery and quarantine management.     

Anatomical-based defense responses of Scots pine (Pinus sylvestris) stems to two fungal pathogens

We investigated the cellular responses of stem tissues of mature Scots pine (Pinus sylvestris L.) trees to inoculations with two fungal pathogens. The bark beetle vectored fungus, Leptographium wingfieldii Morelet, induced longer lesions in the bark, stronger swelling of polyphenolic parenchyma cells, more polyphenol accumulation and increased ray parenchyma activity compared with the root rot fungus, Heterobasidion annosum (Fr.) Bref., or mechanical wounding. Axial resin ducts in the xylem are a general feature of the preformed defenses of Scots pine, but there was no clear induction of additional traumatic axial resin ducts in response to wounding or fungal infection. The anatomical responses of Scots pine to pathogen infection were localized to the infection site and were attenuated away from bark lesions. The responses observed in Scots pine were compared with published studies on Norway spruce (Picea abies (L.) Karst.) for which anatomically based defense responses have been well characterized.     

Dynamic response of stomata to changing irradiance in loblolly pine (Pinus taeda L.)

Dynamic changes in stomatal conductance and the rate of photosynthesis were measured as periods of shading (decrease in irradiance from 800 to 200 micro mol m(-2) s(-1)) between 5 and 60 min were imposed on needles of Pinus taeda L. trees under laboratory conditions. Shading induced a 39% decrease in stomatal conductance but the rate of change was slow. Average time constants (+/- standard error) were shorter for the decrease in stomatal conductance when shading was imposed for 30 min (14.8 +/- 1.3 min) than for the increase in stomatal conductance when shading was removed (25.5 +/- 3.4 min). The time constants for increasing stomatal conductance when shading was removed were linearly related to the length of the previous dark period. The rate of photosynthesis fell immediately by 58% when shading was imposed and increased more rapidly than the change in stomatal conductance when shading was removed. The increase in photosynthesis during the induction phase after shading was removed was limited by both stomatal and biochemical effects. The long time constants for stomatal response contributed to the poor correlations between stomatal conductance and instantaneous measurements of irradiance from field data. However, the slow response of stomatal conductance to changes in irradiance had little effect on total daily transpiration, carbon gain and water-use efficiency.