Concentration gradients of free sterols,steryl esters and lipid phosphorus in the trunkwood of Scot's pine (Pinus sylvestris L.)

The amounts of free sterols, steryl esters and lipid phosphorus were determined in the sapwood and heartwood of mature, and in the outer and inner sapwood of young Pinus sylvestris trees. In the mature trees (up to 70 years old) the heartwood contains significantly higher amounts of free sterols than the sapwood. No radial gradient can be demonstrated in the amounts of steryl esters. Lipids extracted from the sapwood contain higher amounts of phosphorus than those from the heartwood. Stems of young Pinus sylvestris trees (up to 13 years old) show in the inner sapwood higher amounts of both free sterols and steryl esters than the peripheral younger wood zone. The inner sapwood of the young stems shows slightly higher amounts of lipid phosphorus than the outer sapwood. The results indicate that Pinus sylvestris accumulates both free sterols and steryl esters in the stems at a very early stage of the life cycle. Sterol accumulation in the innermost parts of the stems seems not to depend on heartwood formation.     

Components of woody-tissue respiration in young Abies amabilis (Dougl.) Forbes trees

Summary Woody-tissue respiration was measured on five different dates at three to five locations on each of 12 30-year-old Abies amabilis trees. On any given date, temperature-corrected respiration per unit surface area varied 10 to 40-fold between sampling locations. In stems, the two major components of respiration were growth respiration and sapwood maintenance respiration, which were of roughly equal importance during the growing season. There was no evidence of significant cambial maintenance respiration, suggesting that a stand with high bole surface area would not automatically have high respiration. Respiration in branches was much greater than in boles of comparable volume and growth rates, and was significantly correlated with branch height. Branch respiration may include an another significant component in addition to the two seen in bole respiration, possibly associated with carbohydrate mobilization and transport or with CO₂ efflux from the transpiration stream.     

Bias in leaf area — sapwood area ratios and its impact on growth analysis in Pinus contorta

Summary Two alternative estimators of individual tree leaf area (A₁) area are used to derive estimates of leaf-area index (L) for 40 plots in Pinus contorta Dougl. stands. One estimator of A₁ is based on the common assumption of a constant ratio between A₁ and sapwood cross-sectional area at breast height (A_s). The second estimator of A₁ accounts for tree-to-tree variation in the relation between A₁ and A_s. The apparent relationship between stand growth and leaf-area index is strongly dependent on the way leaf area is estimated. When L is derived from a constant A₁A_s ratio, stand growth appears to be strongly correlated with L. However, when L is based on estmates of A₁ that account for tree-to-tree variation in the A₁ — A_s relation, stand growth is seen to be only weakly related to L. Stand structure, quantified as percent live-crown, accounts for a great deal of the observed variation in leaf-area efficiency. These contrasting relationships illustrate the importance of unbiased estimates of L in interpreting the link between stand-level processes and leaf area.Utah Aggriculural Experiment Station Journal Paper No. 3333     

New ellagitannin and galloyl esters of phenolic glycosides from sapwood of Quercus mongolica var. crispula (Japanese oak)

Two novel glycosides, 4,5-dimethoxy-3-hydroxyphenol 1-O-β-(6′-O-galloyl)-glucopyranoside (1) and (+)-2α-O-galloyl lyoniresinol 3α-O-β-d-xylopyranoside (2), as well as a novel ellagitannin named epiquisqualin B (3), were isolated from sapwood of Quercus mongolica var. crispula along with 19 known phenolic compounds. The structures of the novel compounds were elucidated on the basis of chemical and spectroscopic investigation. Compound 2 is the first example of a lignan galloyl ester, and 3 is the oxidation product of vescalagin, which is the major ellagitannin of this plant.     

Variation of heartwood and sapwood in 18-year-old Eucalyptus globulus trees grown with different spacings

Heartwood and sapwood development was studied in 18-year-old Eucalyptus globulus trees from pulpwood plantations with different spacings (3 × 2, 3 × 3, 4 × 3, 4 × 4 and 4 × 5 m), on cross-sectional discs taken at breast height. The trees possessed a large proportion of heartwood, on average 60% of the wood cross-sectional surface. Spacing was a statistically significant source of variation of heartwood area, which ranged between 99 and 206 cm² for the closer (3 × 2) and wider (4 × 5) spacings, respectively. There was a positive and high statistical significant correlation between heartwood diameter and tree diameter (heartwood diameter = −0.272 + 0.616 dbh; r ² = 0.77; P < 0.001), and larger trees contained more heartwood regardless of spacing. Heartwood proportion in cross-section remained practically constant between spacings but increased with tree diameter class: 55.1, 62.2, 65.0 and 69.5% for diameter at breast height classes <15, 15–20, 20–25 and >25 cm, respectively. The sapwood width did not depend on tree diameter growth and remained practically constant at an average of 18 mm (range 15–21 mm), but sapwood area showed a good linear regression with tree diameter. Therefore, tree growth enhancement factors, such as wide spacings, will induce formation of larger heartwoods that can negatively impact raw-material quality for pulping. The increase in heartwood in relation with tree dimensions should therefore be taken into account when designing forest management guidelines.     

大花序桉心边材变异规律和候选基因挖掘研究

为探究大花序桉(Eucalyptus cloeziana)心材比例差异显著的不同家系间心边材变异规律,挖掘心材变异相关的候选基因,为珍贵用材树种高效培育及育种利用提供基因资源。以18 a生的2个心材比例差异显著的大花序桉家系为材料(家系1和2),各制作解析木3株,沿着树干以1 m为区间分段截取圆盘,测量东西和南北2个方向的带皮直径、去皮直径、总年轮数、边材年轮数、边材直径,并开展心材和边材径向和轴向分析。同时利用各解析木胸径处初生木质部样品进行DNA混池测序,发掘等位基因频率差异显著的SNP位点并挖掘相关功能基因。结果表明,大花序桉边材宽度和心材半径的方位变异中家系2大于家系1,平均差值分别为0.7和5.5 cm,在随树高的变异中,家系1和2的心材半径和心材年轮数的下降速率分别为0.40和0.64及0.43和0.36。两家系间基本密度差异显著,家系1为0.80～0.82 g/cm³,家系2为0.75～0.78 g/cm³。基本密度与树高、横截面半径和心材半径呈显著负相关,与顺纹抗拉强度、弦面硬度和部分力学性质呈显著正相关。利用DNA混池测序共...     

Seasonal variation of neutral lipids in Pinus sylvestris L. sapwood and heartwood

Summary The lipid levels and fatty acid composition of three fractions (free fatty acids, triacylglycerols and sterol/triterpenoid esters) extracted from the sapwood and heartwood of three stems of Pinus sylvestris were determined to investigate both seasonal changes in sapwood and possible metabolic changes related to heartwood formation. Seasonal changes were observed only in the amount of the free fatty acids in the sapwood: the level of free fatty acids was greatest at the beginning and end of the growing season. In the January and March samples the amount of the free fatty acid fraction in the sapwood was very small. The amount of the other fractions remained at the same level throughout the study. Marked seasonal changes in the fatty acid composition occurred only in the free fatty acid fraction of the sapwood: the saturation grade increased during the winter.     

Relationships between foliage and conducting xylem in Picea abies (L.) Karst.

Summary The relationship of leaf biomass and leaf area to the conductive area of stems and branches was investigated in Picea abies. A total of 30 trees were harvested to determine if these relationships were different in different crown zones and in trees growing with and without competition for light. Two methods were compared. In the first, data were accumulated from crown zones situated at the top of trees to the bottom; in the second, data were used from individual crown zones. The results indicated that the latter method is much more sensitive in detecting differences in the relationship of leaf biomass or leaf area to conductive area. The analysis also indicated that ratios such as leaf area/sapwood area are frequently size-dependent. This size-dependency can in some cases result in the differences being abscured, but more often leads to the false impression that the relationship between the variables changes. The relationship between leaf biomass and leaf area and conductive area of stems or branches was different in different crown zones and under different growth conditions. The slopes of these regressions appear to increase with decreasing transpirational demand and decrease with increasing hydraulic conductivity. The intercepts are probably related to the amount of identified sapwood actually involved in water conductance.     

Sapwood characteristics of Quercus robur species from the south-western part of the Pannonian Basin

We analysed sapwood characteristics in 344 pedunculate oak (Quercus robur L.) samples from the south-western part of the Pannonian Basin. The samples came from 13 sites, located in Slovenia, Croatia and Serbia. The trees had an average of 13.3 sapwood rings, with a minimum of 5 and maximum of 32. Fifteen log-log linear regression models were employed to assess the statistical relationship between sapwood and heartwood variables. The number of sapwood rings (N_SW), which is usually needed in dendroarchaeological dating, is significantly related to the number of heartwood rings (N_HW), heartwood width (W_HW) and heartwood growth rate (G_HW). Older and more slowly growing trees had a higher average number of sapwood rings. Using N_HW and W_HW, we employed an additional multiple regression model and calculated coefficients for N_SW predictions for real-world dendroarchaeological dating from the south-western part of the Pannonian Basin.     

Formation and vertical distribution of sapwood and heartwood in Cryptomeria japonica D. Don

The formation and vertical distribution of sapwood and heartwood were studied with a 45-year-old Cryptomeria japonica D. Don. The tree was grown at a plantation with 1.5 m × 3.0 m spacing near Miao-Li, Taiwan and was felled on 27 February 1992. The thickness of sapwood and heartwood was expressed by a ring count and a linear measurement. The east-west (E-W) wood strips were collected from 0.3 m above ground upwards to the top of the tree at 2.5 m intervals. The sapwood thicknesses from the base to the 10.3 m tree level height are around 20–22 growth rings and 42±2 mm. At the top of the tree, the sapwood thickness is narrower. The heartwood, which decreases in thickness with increasing tree level heights is not found at the top of the tree. The heartwood appears as a conical shape in the tree trunk. There is no statistical difference in sapwood/heartwood thickness between E-W aspects. Tree level heights and the tree level age were found to be important parameters in determining the thickness of sapwood/heartwood.