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1.
Inherited narrow crown form, harvest index and stem biomass production in Norway spruce, Picea abies
The effect of crown form on stem biomass production was investigated in an 18-19-year-old Norway spruce stand (Picea abies (L.) Karst.). The harvest index was 0.271 in pendula trees, which have a heritable narrow crown form, and 0.235 in normal-crowned trees and the dry weights of stem biomass were 2.57 kg and 3.37 kg, respectively. However, the production of stem biomass per crown projected area was more than twice as much in pendula trees as in normal-crowned trees. Results indicate that the crown form of pendula spruce is less plastic than that of normal-crowned spruce suggesting that such trees might maintain a high stemwood yield per unit ground area with increasing stand density. Because pendula spruce has a higher harvest index and a less flexible crown than normal-crowned spruce, it might be useful for crop tree ideotype breeding. 相似文献
2.
Timo Kuuluvainen 《Forest Ecology and Management》1991,40(3-4):243-260
Sample tree material was reanalyzed in order to study the relationships between horizontal crown projected area and components of above-ground biomass in Norway spruce (Picea abies (L.) Karst.) trees growing in even-aged stands. The needle mass of dominant trees increased linearly with the increase in crown projected area, but in co-dominant and dominanted trees the increase in needle mass levelled off toward larger crown projected areas. The branch mass of dominant and co-dominant trees accumulated faster than linearly with increasing crown projected area, whereas in dominated trees an approximately linear relationship existed between these two variables. The increase in needle and branch mass per unit increase in crown projected area was highest in dominant trees and decreased to co-dominant and dominated trees, i.e. with tree position in the canopy. The stem mass accumulated obviously faster than linearly and similarly in all tree classes with the increase in crown projected area. The narrow crown shape indicated a high density of all components of above-ground biomass per unit of crown projected area. 相似文献
3.
The production and allocation of aboveground biomass and the characteristics of tree architecture were examined in eight-year-old Scots pine (Pinus sylvestris L.). Considerable among-tree variation existed in tree architecture, total aboveground dry mass production, and dry mass partitioning among tree parts. A linear relationship existed between needle and branch mass. Stem mass was directly proportional to tree height, which in turn was directly proportional to the allocation ratio between stem mass and total needle + branch mass production. The architectural characteristics that were related to a high proportional allocation to stem and high stemwood production were a large mean shoot volume, large mean number of branches per whorl, long needle retention and a high crown length/crown width ratio. Individual trees were found that combined high stemwood production with both high harvest index and high stemwood specific gravity. 相似文献
4.
《Forest Ecology and Management》1996,88(3):237-247
The aim of this study was to examine the variation in tree architecture and needle efficiency in stemwood production in Norway spruce in relation to tree age and altitude of growing site. The data, which were obtained from the literature, described individual Norway spruce (Picea abies (L.) Karst.) trees from even-aged stands in Switzerland. Second-order trend surface models, with tree age and altitude as independent variables, were used in the analysis. The fitted models for stem, branch and needle dry masses explained 95%, 75% and 64% of the variation, respectively. The model for the estimated mean branch density in the crown (kg m−3) explained 64% of the variation and the model for mean needle density in the crown (kg m−3) only 28% of the variation. Crown structural characteristics, which showed age- and altitude-related variations, included live crown ratio (59% of variation explained), number of living whorls (43% of variation explained), mean weight of single needle (40% of variation explained) and specific needle area (27% of variation explained). Tree age had a strong effect on needle efficiency in stemwood production, so that needle efficiency increased up to the age of 50–70 years, depending on altitude. 相似文献
5.
Leaf and crown morphology of shade-tolerant sugar maple (Acer saccharum Marsh.) were examined to test the hypotheses (1) that leaf area exhibits significant plasticity both within and between crown classes and individual tree crowns and (2) that leaf area is accurately predicted from estimates of crown volume. A total of 18 trees, ranging from 3.3 to 43.4 cm dbh, were felled and dissected into upper, middle, lower, and below-crown layers, for measurements of leaf, bark, and xylem dimensions. For dominant trees only, bark thickness and xylem radii were higher within the crown than below the crown. Cumulative leaf area index increased with decreasing stratum height at similar rates in all trees, except for two trees that were located in the understory. Area leaf weight declined with decreasing stratum height within the crown of all except four overstory trees. These four trees showed an increase with decreasing stratum height, i.e., leaves were heavier per unit area in the lower crown stratum and below the crown than they were at mid-crown. Within-tree leaf area density was usually higher in the upper crown of overstory trees and in the lower crown of understory trees. Total crown volume was the best predictor of whole-tree leaf area, but it was only slightly better than dbh. 相似文献
6.
杨树新无性系冠层特性与生长关系研究 总被引：14，自引：1，他引：13
对 5年生黑杨无性系的冠层特性与材积生长之相关性进行了研究。材积生长与全树总叶面积TLA、树冠表面积TCA和冠型率CSR呈极显著正相关而与叶面积指数LAI、冠层密度CLD呈负相关。冠层内上、中层的叶面积对材积生长起了决定性作用 ,下层叶面积与材积生长关系不大。水平方向 ,冠层内、外部叶面积特性对材积生长贡献较大 ,而中部叶面积特性贡献小。阐明了杨树生长的理想冠层特性。 相似文献
7.
We compared the range and variation in shoot silhouette area to projected leaf area ratio (SPAR) in fertilized and unfertilized (control) Norway spruce (Picea abies (L.) Karst.) trees. We measured SPAR for several view directions of 169 shoots at different depths in the crown of fertilized and control trees. There was an increase in SPAR with depth in the crown in both control and fertilized trees. In the fertilized trees, however, mean SPAR was larger overall, the increase with depth in the crown was steeper, and there was a larger variation in SPAR with inclination and rotation angle of the shoot (relative to the view direction). In particular, shoots in the lower crown of fertilized trees were rotationally asymmetrical ("flat") and had high values of the maximum ratio of shoot silhouette area to projected leaf area (SPAR(max)). Differences in SPAR between fertilized and control trees were explained by changes in shoot structure in response to fertilization and shading. Shoots of fertilized trees were larger and had more needle area than shoots of control trees. However, the ratio of needle area to shoot size was smaller in fertilized trees than in control trees, implying less within-shoot shading and, consequently, a larger SPAR. Also, the increase in SPAR with increased shading (depth in the crown) could be explained by a decrease in the ratio of needle area to shoot size. In addition, because fertilized trees had more needle area than control trees, the effect of shading at a given depth in the crown was more pronounced in fertilized trees than in control trees. 相似文献
8.
Crown architecture and growth allocation were studied in saplings of eastern white pine (Pinus strobus L.), a species classified as intermediate in shade tolerance. A comparison was made of 15 understory saplings and 15 open-grown saplings that were selected to have comparable heights (mean of 211 cm, range of 180-250 cm). Mean ages of understory and open-grown trees were 25 and 8 years, respectively. Understory trees had a lower degree of apical control, shorter crown length, and more horizontal branch angle, resulting in a broader crown shape than that of open-grown trees. Total leaf area was greater in open-grown saplings than in understory saplings, but the ratio of whole-crown silhouette (projected) leaf area to total leaf area was significantly greater in understory pine (0.154) than in open-grown pine (0.128), indicating that the crown and shoot structure of understory trees exposed a greater percentage of leaf area to direct overhead light. Current-year production of understory white pine was significantly less than that of open-grown white pine, but a higher percentage of current-year production was allocated to foliage in shoots of understory saplings. These modifications in crown structure and allocation between open-grown and understory white pine saplings are similar to those reported for more shade-tolerant fir (Abies) and spruce (Picea) species, but the modifications were generally smaller in white pine. As a result, white pine did not develop the flat-topped "umbrella" crown structure observed in understory fir and spruce, which approaches the idealized monolayer form that maximizes light interception. The overall change to a broader crown shape in understory white pine was qualitatively similar, but much more limited than the changes that occurred in fir and spruce. This may prevent white pine from persisting in understory shade as long as fir and spruce saplings. 相似文献
9.
Needle dimensions, needle surface area, needle dry weight per area (LWA) and needle density (ND, needle weight per volume) were measured in terminal current-year shoots in a natural canopy of variably sized Picea abies (L.) Karst. trees growing along a light gradient. Needle shape was described as a rhomboid. Needle width (D(2)) increased with increasing diffuse site factor, a(d) (relative amount of penetrating diffuse solar radiation), whereas needle thickness (D(1)) remained nearly constant, resulting in an inverse relationship between D(1)/D(2) and a(d) and an increase in the ratio of total (TLA) to projected needle surface area (PLA) with increasing a(d). Because of the variations in needle morphology with respect to light availability, the shoot parameters used in present canopy models are also expected to be light-sensitive, and studies involving shoot morphology should also consider the variability in needle geometry. Needle dimensions and total tree height were not correlated. However, LWA increase with both increasing a(d) and total tree height. When LWA was expressed as the product of ND and needle height (NH, height of the rhomboidal transverse section of a needle), LWA appeared to increase with irradiance, because of changing NH, and with total tree height, because of changing needle density. 相似文献
10.
We investigated effects of nutrient availability on shoot structure and light-interception efficiency based on data from control (C) and irrigated + fertilized (IL) trees of Norway spruce (Picea abies (L.) Karst.). The sampling of 1-year-old shoots was designed to cover the variation in canopy exposure within the live crown zone, where current-year shoots were still found. Canopy openness was used as a measure of light availability at the shoot's position. Openness values for the sample shoots ranged from 0.02 to 0.77 on the IL plot, and from 0.10 to 0.96 on the C plot. Among needle dimensions, needle width increased most with canopy openness. At fixed canopy openness, needle width was larger, and the ratio of needle thickness to width was smaller in IL trees than in C trees. Specific needle area (SNA) and the ratio of shoot silhouette area to total needle area (STAR) decreased with canopy openness, so that the combined effect was a threefold decrease in the ratio of shoot silhouette area to unit dry mass (SMR = STAR x SNA) along the studied range of openness values. This means that the light-interception efficiency of shoots per unit needle dry mass was three times higher for the most shaded shoots than for sun shoots. A test of the effect of fertilization on the relationships of SNA, STAR and SMR indicated statistically significant differences in both slope and intercept for SNA and STAR, and in the intercept for SMR. However, the differences partly cancelled each other so that, at medium values of canopy openness, differences between treatments in predicted SNA, STAR and SMR were small. At 0.5 canopy openness, predicted STAR of IL shoots was 6.1% larger than STAR of C shoots, but SMR of IL shoots was 10% smaller than that of C shoots. The results suggest that light-interception efficiency per unit needle area or mass of the shoots is not greatly affected by fertilization. 相似文献
11.
We compared shoot and needle morphology and photosynthesis in Picea glehnii (Friedr. Schmidt) M.T. Mast. and Picea jezoensis (Sieb. et Zucc.) Carr. trees planted on immature volcanic ash and well-developed brown forest soils to investigate whether species differences in morphological and physiological plasticity affected tree growth on different soil types. Height growth of P. glehnii was reduced by about 10% on volcanic ash compared with forest soil, whereas that of P. jezoensis was reduced by more than 60%. Needle morphology of P. glehnii was unaffected by soil type. In contrast, needles of P. jezoensis trees growing on volcanic ash were shorter, narrower and thicker, with less dry mass and area, than those of trees growing on forest soil, and specific needle area was lower, indicating lower foliar light-interception efficiency. In both species, changes in needle morphology with increasing irradiance were similar in trees growing on both soil types, indicating that plasticity of needle morphology was unaffected by soil type. In both species, shoot mass and shoot silhouette area were lower and needle mass per unit shoot mass was higher in trees growing on volcanic ash than in trees growing on forest soil. Trees of both species had more needles per unit shoot length, lower shoot silhouette to projected needle area ratios and lower shoot silhouette areas per unit shoot mass (SAM) on volcanic ash than on forest soil, indicating lower shoot-level light-interception efficiency. For P. glehnii, the response of shoot morphology to increasing irradiance was similar on both soil types, with the exception of SAM, which showed lower plasticity in trees growing on volcanic ash. In contrast, shoot-level morphological plasticity of P. jezoensis was reduced in trees growing on volcanic ash. Light-saturated maximum photosynthetic rate (P(max)) of P. glehnii was unaffected by soil type, whereas mass-based P(max) of P. jezoensis was lower in trees growing on volcanic ash than in trees growing on forest soil. In P. jezoensis trees growing on forest soil, area-based P(max) increased with increasing irradiance, but this response was not observed in trees growing on volcanic ash. As a result, area-based P(max) at the top of the canopy was 39 to 54% lower in trees growing on volcanic ash than in trees growing on forest soil. Our results indicate that constraints on morphological acclimation to high irradiances may contribute to reduced height growth of P. jezoensis on volcanic ash. 相似文献
12.
Altitudinal differences in the leaf fitness of juvenile and mature alpine spruce trees (Picea crassifolia) 总被引：4，自引：0，他引：4
In many plant species, leaf morphology varies with altitude, an effect that has been attributed to temperature. It remains uncertain whether such a trend applies equally to juvenile and mature trees across altitudinal gradients in semi-arid mountain regions. We examined altitude-related differences in a variety of needle characteristics of juvenile (2-m tall) and mature (5-m tall) alpine spruce (Picea crassifolia Kom.) trees growing at altitudes between 2501 and 3450 m in the Qilian Mountains of northwest China. We found that stable carbon isotope composition (delta(13)C), area- and mass-based leaf nitrogen concentration (N(a), N(m)), number of stomata per gram of nitrogen (St/N), number of stomata per unit leaf mass (St/LM), projected leaf area per 100 needles (LA) and leaf mass per unit area (LMA) varied nonlinearly with altitude for both juvenile and mature trees, with a relationship reversal point at about 3100 m. Stomatal density (SD) of juvenile trees remained unchanged with altitude, whereas SD and stomatal number per unit length (SNL) of mature spruce initially increased with altitude, but subsequently decreased. Although several measured indices were generally found to be higher in mature trees than in juvenile trees, N(m), leaf carbon concentration (C(m)), leaf water concentration (LWC), St/N, LA and St/LM showed inconsistent differences between trees of different ages along the altitudinal gradient. In both juvenile and mature trees, delta(13)C correlated significantly with LMA, N(m), N(a), SNL, St/LM and St/N. Stomatal density, LWC and LA were only significantly correlated with delta(13)C in mature trees. These findings suggest that there are distinct ecophysiological differences between the needles of juvenile and mature trees that determine their response to changes in altitude in semi-arid mountainous regions. Variations in the fitness of forests of different ages may have important implications for modeling forest responses to changes in environmental conditions, such as predicted future temperature increases in high altitude areas associated with climate change. 相似文献
13.
Morphology and chemical composition of needles of shade-intolerant southern conifers (Pinus palustris Mill. (mean needle length +/- SD = 29.1 +/- 4.1 cm), P. taeda L. (12.3 +/- 2.9 cm) and P. virginiana Mill. (5.1 +/- 0.8 cm)) were studied to test the hypothesis that foliage acclimation potential to canopy light gradients is generally low for shade-intolerant species, and in particular, because of mechanical limitations, in species with longer needles. Plasticity for each needle variable was defined as the slope of the foliar characteristic versus irradiance relationship. A novel geometrical model for needle area and volume calculation was employed for the three-needled species P. palustris and P. taeda. Needle thickness (T) strongly increased, but width (W) was less variable with increasing daily integrated quantum flux density averaged over the season (Q(int)), resulting in changes in cross-sectional needle shape that were manifested in a positive relationship between the total to projected needle area ratio (A(T)/A(P)) and Q(int) in the three-needled species. In contrast, cross-sectional needle geometry was only slightly modified by irradiance in the two-needled conifer P. virginiana. Needle dry mass per unit total needle area (M(T)) was positively related to Q(int) in all species, leading to greater foliar nitrogen contents per unit area at higher irradiances. Separate examination of the components of M(T) (density (D) and the volume (V) to A(T) ratio; M(T) = DV/A(T)) indicated that the positive effect of light on M(T) resulted solely from increases in V/A(T), i.e., from increases in the thickness of foliage elements. Foliar chlorophyll content per unit mass increased with increasing Q(int), allowing an improvement in light-harvesting efficiency in low light. The variables characterizing needle material properties (D, the dry to fresh mass ratio, and needle carbon content per unit mass) were generally independent of Q(int), suggesting that needles were less stiff and had greater tip deflections under their own weight at lower irradiances because of smaller W and T. Comparisons with the literature revealed that plasticity in foliar characteristics tended to be lower in the studied shade- intolerant species than in shade-tolerant conifers, but plasticity among the investigated species was unaffected by needle length. However, we argue that, because of mechanical limitations, plastic changes in needle cross section in response to low irradiance may decrease rather than increase light-interception efficiency in long-needled species. 相似文献
14.
The projected leaf area index (LAI) of a mature stand of Scotspine (Pinus sylvestris L.) at Thetford Forest, south-east Englandwas measured by sampling the needle populations on harvestedand wind-thrown trees covering the range of girth sizes. Thevertical distribution of leaf area for individual trees waspolymodal while that for the canopy as a whole was adequatelydescribed by the curve for a normal distribution with the inclusionof a term for positive skewness. The fitted curve defined themidpoint of the canopy at a height of 14.3 m and the standarddeviation of leaf area with respect to height as 13% of thecanopy depth. The fitted curve explained 90 per cent of thevariation and the estimates of the parameters were close tothe measured values. Using previous measurements showing that needle production andfall could be described by linear regression equations, a modelwas developed to predict the annual changes of current and oldneedles in a closed canopy. The maximum LAI at Thetford was2.73 on 12th August of which 36 per cent was new (current) needles.Leaf area index varied by only 7 per cent between November toMay inclusive; higher values occurred between June and Octoberat times of potentially high photosynthetic and transpirationrates. The leaf characteristics of the stand were similar to thoseof a stand of Scots pine of similar age at Roseisle in north-eastScotland. 相似文献
15.
Zhenmin Tang Jim L. Chambers Suresh Guddanti Shufang Yu James P. Barnett 《Forest Ecology and Management》1999,120(1-3):117-130
The impacts of thinning, fertilization and crown position on seasonal growth of current-year shoots and foliage were studied in a 13-year-old loblolly pine (Pinus taeda L.) plantation in the sixth post-treatment year (1994). Length of new flushes, and their needle length, leaf area, and oven-dry weight were measured in the upper and lower crown from March through November. Total shoot length was the cumulative length of all flushes on a given shoot and total leaf area per shoot was the sum of leaf areas of the flushes.
By the end of June, first-flush foliage reached 70% of the November needle length (14.3 cm) and 65% of the final leaf area (15.0 cm2). Cumulative shoot length of first- and second-flush shoots achieved 95% of the annual length (30.3 cm), whereas total leaf area per shoot was 55% of the final value (75.3 dm2). Fertilization consistently stimulated fascicle needle length, dry weight, and leaf area in the upper crown. Mean leaf area of upper-crown shoots was increased by 64% six years after fertilization. A significant thinning effect was found to decrease mean leaf area per shoot in the crown. For most of the growing season, the thinned-fertilized trees produced substantially more leaf area per shoot throughout the crown than the thinned-nonfertilized trees. These thinned-fertilized trees also had greater needle length and dry weight, longer first flush shoots, and more leaf area per flush than trees in the thinned-nonfertilized plots. Needle length and leaf area of first flush shoots between April and July were linearly related to previous-month canopy air temperature (Ta). Total shoot length strongly depended on vertical light gradient (PPFD) within the canopy, whereas shoot leaf area was a function of both PPFD and Ta. Thus, trees produced larger and heavier fascicles, more and longer flush shoots, and more leaf area per shoot in the upper crown than the lower crown. We conclude that thinning, fertilization, and crown position regulate annual leaf area production of current-year shoots largely by affecting the expansion of first flush shoots and their foliage during the first half of the growing season. 相似文献
16.
《Scandinavian Journal of Forest Research》2012,27(1-4):185-200
The growth and structural development of Scots pine (Pinus sylvestris L.) trees growing at different spacing was simulated using a model based on the dry matter production per needle biomass unit and its allocation to needles, branches and stem. Special emphasis was given to the effect of stand density on the growth of the crown system and its implications on branchiness and timber quality. The simulations showed that the needle biomass culminates considerably earlier than the branch biomass with a time lag inversely related to the stand density. The lengths of living and dead crown were also inversely related to stand density. The resulting differences in branchiness were especially obvious in the early development of the tree stands. In the long run these differences tend to disappear, indicating equal external branchiness independently of the initial spacing for mature stands of Scots pine. The internal branchiness, however, was particularly sensitive to the initial spacing. 相似文献
17.
Crown architecture of Abies balsamea from four canopy positions 总被引：1，自引：0，他引：1
Data collected from four distinct canopy positions from each of 39 Abies balsamea (L.) Miller trees were used to construct models to describe the cumulative leaf area distribution within the crown and to predict the needle mass of individual branches, the average branch angle, branch diameter, branch length, and crown radius per whorl, and the average number of living branches per whorl. We tested the hypotheses that regression models are equal among canopy positions and that a model to predict branch needle mass is valid at the northern and southern extremes of the central climatic zone of Maine. Canopy position had an effect on the models constructed to predict needle mass, branch angle, branch diameter, branch length, crown radius, and the number of living branches per whorl. However, compared with an expanded model that incorporated parameters calculated for each crown class, there was only a small loss in model precision when a general model constructed from data pooled from all crown classes was used to predict needle mass, branch angle, and branch diameter. Regression equations unique to each crown class were needed to predict crown shape and leaf area distribution in the crown satisfactorily. Our branch needle mass model, which was constructed from data collected at the southern extreme of the central climatic zone of Maine, consistently underestimated needle branch mass when applied to the northern extreme of the central climatic zone. 相似文献
18.
《Scandinavian Journal of Forest Research》2012,27(1-4):251-263
Although a good correlation has been found between the mean degree of damage and the increment trend of larger Norway spruce collectives, individual spruce trees often betray no relationship between crown damage and the development of the volume increment. Detailed investigations show that stem and crown dimensions, growing space as well as the competition of neighboring stems can substantially outweigh the influence of crown damage on the volume increment. Furthermore, current methods to determine crown parameters and needle loss are in many cases quite error‐prone. Use of more accurate techniques for measuring spruce trees produced a stronger relation between the volume increment per square meter crown surface area and the degree of crown damage (needle loss). 相似文献
19.
Aboveground xylem hydraulic conductance was determined in Scots pine (Pinus sylvestris L.) trees and stands from 7 to about 60 years of age. At the stand scale, leaf area index and net primary productivity (NPP, above- plus belowground) increased and reached a plateau at about 25-30 and 15-20 years, respectively; both parameters declined in mature stands. Stand hydraulic conductance followed a similar trend to NPP, with a maximum at about 15-20 years and a pronounced reduction in old stands. At the tree scale, annual biomass growth per unit of leaf area (growth efficiency) declined with tree age, whereas aboveground sapwood volume per unit leaf area, which is linearly related to maintenance respiration costs, steadily increased. Radiation interception per unit leaf area increased significantly with reduced leaf area index of mature stands, despite increased foliage clumping in the canopies of mature trees. Needle nutrient concentration did not change in the chronosequence. Tree hydraulic conductance per unit leaf area was strongly and positively correlated with growth efficiency. We discuss our findings in the context of growth reductions in mature and old trees, and suggest that increased hydraulic resistance and maintenance respiration costs may be the main causes of reduced carbon gain in mature and old trees. 相似文献
20.
《Scandinavian Journal of Forest Research》2012,27(1-4):455-472
The branch biomass of young Scots pines (Pinus sylvestris L.) was inversely related to the branch number per projected crown area giving greater branch density and smaller branch biomass for narrow crowns than for broad crowns. In particular, in dense stands the small share of branches from the total biomass of narrow‐crowned trees was emphasized. The productivity of narrow crowned trees was, however, smaller than that of trees with broad crowns. The concept of the tree ideotype has been discussed on the basis of theoretical calculations. 相似文献