共查询到20条相似文献，搜索用时 31 毫秒
1.
Reza Oladi Elham Elzami Kambiz Pourtahmasi Achim Bräuning 《European Journal of Forest Research》2017,136(2):345-356
A better understanding of the ecophysiological basis of wood formation by monitoring radial growth over the whole vegetation period may help to explain possible discrepancies between long-term average climate–growth relationships and short-term climatic impacts on tree growth. To understand how growth–climate associations of Oriental beech vary throughout a vegetation period, we studied seasonal growth patterns of high-elevation beech trees growing in the north of Iran by collecting wood anatomical micro-cores in 10 to bi-weekly intervals and measuring stem increment with high-resolution electronic dendrometers. Wood formation was for two consecutive years with contrasting inter-annual climate conditions (2011 and 2012). We divided the growing period into three equal time phases and related daily climate variability to the cambial growth in each phase. The pattern of climate–growth relationships varies over a complete growing season and between years: in both study years, trees responded homogenously at the beginning and at the end of the growing season, but showed opposing influence of relative humidity during spring and early summer (June and July). Temperature as the main driver of xylogenesis had a stimulating effect on growth at the beginning of the growing season, but had negative effects on radial increment during late June and July mainly due to the excess of ambient temperatures over an optimum threshold. Higher temperature in late June and July 2011 compared with those of 2012 led to a significantly narrower tree ring in 2011, despite the similar sums/means of annual climate parameters in these two years. Since regional climate change scenarios expect higher temperature and reduced moisture conditions in future, radial growth of beech in the north of Iran may be adversely affected. 相似文献
2.
David M. Drew Geoffrey M. Downes Anthony P. O’Grady Jennifer Read Dale Worledge 《Annals of Forest Science》2009,66(4):406-406
3.
In 1990, a 2-ha plantation of Eucalyptus nitens (Deane and Maiden) Maiden was established in southeastern Tasmania and subjected to different irrigation regimes. Point dendrometers were installed in March 1995 to monitor radial stem movement every 15 min over several growing seasons. In this study, data from two growing seasons (1996-1998) were considered. From these measurements, daily increments of stem radius were determined. At the end of the second growing season, we extracted 12-mm cores and measured microfibril angles (MFA) of the wood at high resolution. Microfibril angles were rescaled on a time axis and mapped to daily and distance-based elements. Among treatments, irrigated trees in particular formed higher MFA early in the growing season (September-November) and lower MFA later in the growing season. Trees subjected to cyclic droughts showed clear relationships between MFA and soil water deficits, with MFA increasing in response to water stress release. Increases in MFA were preceded by accelerations in daily increment of stem radius. Among treatments, trees subjected to severe drought had the smallest MFA and generally low fluctuations in MFA. Irrigated trees were susceptible to changes in climate, whereas growth of the trees in the other treatments was limited by water availability. Use of path-analysis showed that temperature had an effect on stem radius increment but not on MFA; wind speed was the only factor that influenced MFA directly. Microfibril angle was correlated with stem shrinking and expansion phases; growth period length and growth rates were positively related to MFA. 相似文献
4.
Monitoring cambial phenology and intra-annual growth dynamics is a useful approach for characterizing the tree growth response to climate change. However, there have been few reports concerning intra-annual wood formation in lowland temperate forests with high time resolution, especially for the comparison between deciduous and coniferous species. The main objective of this study was to determine how the timing, duration and rate of radial growth change between species as related to leaf phenology and the dynamics of non-structural carbohydrates (NSC) under the same climatic conditions. We studied two deciduous species, Fagus sylvatica L. and Quercus petraea (Matt.) Liebl., and an evergreen conifer, Pinus sylvestris L. During the 2009 growing season, we weekly monitored (i) the stem radial increment using dendrometers, (ii) the xylem growth using microcoring and (iii) the leaf phenology from direct observations of the tree crowns. The NSC content was also measured in the eight last rings of the stem cores in April, June and August 2009. The leaf phenology, NSC storage and intra-annual growth were clearly different between species, highlighting their contrasting carbon allocation. Beech growth began just after budburst, with a maximal growth rate when the leaves were mature and variations in the NSC content were low. Thus, beech radial growth seemed highly dependent on leaf photosynthesis. For oak, earlywood quickly developed before budburst, which probably led to the starch decrease quantified in the stem from April to June. For pine, growth began before the needles unfolding and the lack of NSC decrease during the growing season suggested that the substrates for radial growth were new assimilates of the needles from the previous year. Only for oak, the pattern determined from the intra-annual growth measured using microcoring differed from the pattern determined from dendrometer data. For all species, the ring width was significantly influenced by growth duration and not by growth rate, which differs from previous studies. The observed between-species difference at the intra-annual scale is key information for anticipating suitability of future species in temperate forests. 相似文献
5.
Radial stem growth in response to microclimate and soil moisture in a drought-prone mixed coniferous forest at an inner Alpine site 总被引：1，自引：0，他引：1
Walter Oberhuber Andreas Gruber Werner Kofler Irene Swidrak 《European Journal of Forest Research》2014,133(3):467-479
Dendroclimatological studies in a dry inner Alpine environment (750 m a.s.l.) revealed different growth response of co-occurring coniferous species to climate, which is assumed to be caused by a temporal shift in wood formation among species. The main focus of this study therefore was to monitor intra-annual dynamics of radial increment growth of mature deciduous and evergreen coniferous species (Pinus sylvestris, Larix decidua and Picea abies) during two consecutive years with contrasting climatic conditions. Radial stem growth was continuously followed by band dendrometers and modelled using Gompertz functions to determine time of maximum growth. Histological analyses of tree ring formation allowed determination of temporal dynamics of cambial activity and xylem cell development. Daily fluctuations in stem radius and radial stem increments were extracted from dendrometer traces, and correlations with environmental variables were performed. While a shift in temporal dynamics of radial growth onset and cessation was detected among co-occurring species, intra-annual radial growth peaked synchronously in late May 2011 and early June 2012. Moist atmospheric conditions, i.e. high relative air humidity, low vapour pressure deficit and low air temperature during the main growing period, favoured radial stem increment of all species. Soil water content and soil temperature were not significantly related to radial growth. Although a temporal shift in onset and cessation of wood formation was detected among species, synchronous culmination of radial growth indicates homogenous exogenous and/or endogenous control. The close coupling of radial growth to atmospheric conditions points to the importance of stem water status for intra-annual growth of drought-prone conifers. 相似文献
6.
Seasonal dynamics of wood formation: a comparison between pinning,microcoring and dendrometer measurements 总被引：1，自引：1，他引：0
Harri Mäkinen Jeong-Wook Seo Pekka Nöjd Uwe Schmitt Risto Jalkanen 《European Journal of Forest Research》2008,127(3):235-245
Three different methods were evaluated for analysing wood formation of Norway spruce [Picea abies (L.) Karst.] and Scots pine (Pinus sylvestris L.) in Finland. During two growing seasons, wood formation dynamics were determined both by wounding the cambium with a needle
followed by localisation of the wound-associated tissue modification after the growing season (pinning), and by extracting
small increment cores during the growing season (microcoring). Stem radius was additionally monitored with band dendrometers.
For Norway spruce, pinning and microcoring yielded similar dates for the onset of wood formation. The timing of wood production
during the growing season was also similar for pinning and microcoring. For Scots pine, the onset of wood formation was recorded
from microcores almost 2 weeks later than from pinning samples. In Scots pine, microcore measurements also produced somewhat
later cessation dates for tracheid formation than the pinning samples. For both tree species, the total number of tracheids
formed during the growing season was, however, about the same for pinning and microcoring. Dendrometer results clearly differed
from those of pinning and microcoring. In particular, the dendrometers showed an increase of stem radius considerably earlier
in spring, when the other methods did not detect wood formation. Thus, pinning and microcoring currently represent the most
reliable techniques for detailed monitoring of wood formation. 相似文献
7.
Alejandro Martinez-Meier Leopoldo Sanchez Mario Pastorino Leonardo Gallo Philippe Rozenberg 《Forest Ecology and Management》2008,256(4):837-843
In a global warming scenario, drought and heat waves like the one that occurred in 2003 in Europe are expected to become more intense and frequent. This extreme climate event strongly affected the hydraulic balance in many forest tree species including Douglas-fir, with symptoms ranging from partial crown necrosis to death. We studied a French Douglas-fir provenance trial, strongly affected by the 2003 drought and heat wave. Using wood X-ray microdensity profiles as a record of cambium response to environmental variations, we compared mean stem density and growth between dead and alive neighbouring trees and several microdensity characters measured over 17 growth rings previous to 2003. Special attention has been given to the sampling layout in order to minimize the micro-environmental effects. At tree level, surviving trees have a significantly higher mean stem density. At tree ring level, they have a significantly higher mean ring density, maximum ring density, latewood density and, to a lesser extent, latewood proportion. No significant difference was found for diameter growth. These results could have direct implications in the way to study and predict possible acclimation and adaptation of forest trees to climate change process. Wood could be used for the selection of genotypes with a desirable plasticity and resistance to drought induced-cavitation. 相似文献
8.
We tested the hypothesis that broad-leaved forest species with contrasting wood anatomy and hydraulic system (ring-porous versus diffuse-porous) also differ in distribution and seasonal dynamics of carbohydrate reserves in stem wood. Total nonstructural carbohydrate (TNC) reserves (starch and sugars) were measured enzymatically in the 10 youngest stem xylem rings of adult oak (Quercus petraea (Matt.) Liebl.) and beech (Fagus sylvatica L.) trees during an annual cycle. Radial distribution of carbohydrates was investigated according to ring age. On all dates, oak trees had twofold higher TNC concentration than beech trees (41 versus 23 mg g(DM)(-1)), with starch accounting for the high TNC concentration in oak. Seasonal dynamics of TNC concentration were significantly (P < 0.05) more pronounced in oak (20-64 mg TNC g(DM)(-1)) than in beech (17-34 mg TNC g(DM)(-1)). A marked decrease in TNC concentration was observed in oak trees during bud burst and early wood growth, whereas seasonal fluctuations in TNC concentrations in beech trees were small. The radial distribution of TNC based on ring age differed between species: TNC was restricted to the sapwood rings in oak, whereas in beech, it was distributed throughout the wood from the outermost sapwood ring to the pith. Although the high TNC concentrations in the outermost rings accounted for most of the observed seasonal pattern, all of the 10 youngest xylem rings analyzed participated in the seasonal dynamics of TNC in beech trees. The innermost sapwood rings of oak trees had low TNC concentrations. Stem growth and accumulation of carbon reserves occurred concomitantly during the first part of the season, when there was no soil water deficit. When soil water content was depleted, stem growth ceased in both species, whereas TNC accumulation was negligibly affected and continued until leaf fall. The contrasting dynamics and distribution of carbohydrate reserves in oak and beech are discussed with reference to differences in phenology, early spring growth and hydraulic properties between ring-porous trees and diffuse-porous trees. 相似文献
9.
Joana Vieira Sergio Rossi Filipe Campelo Cristina Nabais 《European Journal of Forest Research》2014,133(1):41-50
Neighboring trees growing under identical environmental conditions can exhibit different dynamics and periods of growth. Despite the recent advances in cambial biology, the exogenous and endogenous factors generating asynchronous xylem growths still remain undetermined. This study investigated timings and duration of xylem formation in maritime pine (Pinus pinaster Ait.) from an even-aged plantation in Portugal growing under Mediterranean climate. Cambial phenology and stem diameter were monitored weekly, from March to December 2010, on two classes of trees divided according to the tree ring widths of the last 15 years, but similar age and size: fast- and slow-growing trees. We tested the hypothesis that differences in tree ring widths result from cell production which in turn affects timings of xylogenesis and that the bimodal growth pattern, typical of the Mediterranean, originates from a double reactivation of the cambium: in spring and autumn. Cambial activity started earlier and ended later in fast-growing trees, confirming that cell production is a key factor determining the duration of xylogenesis. Intra-annual variations in stem diameter recorded by band dendrometers revealed two peaks of increment occurring in spring and late summer. However, the number of cambial cells did not increase in late summer, which suggested that the second peak of increment was caused by stem rehydration, rather than by a reactivation of cell division. These results demonstrated that the variability in the timings of xylem phenology observed among trees of the same age and size and growing under similar environmental conditions was closely related to cell production and not to age or size per se. 相似文献
10.
《林业研究》2020,31(5)
The explicit purpose of this study was to characterize climate and vegetation along the western slope of the El Sira Mountains(Peru) and evaluate radial tree growth in response to seasonal rainfall anomalies. From May 2011 until September 2015, we monitored radial stem growth of 67 trees using point dendrometers and measured climate within five sites along an altitudinal gradient. The transect extends from lowland terra firme forests, over submontane forests, late and mid successional montane cloud forests up to exposed elfin forests. Monthly rainfall estimates by the TRMM PR satellite(product 3B42) were highly correlated with our rain gauge observations but underestimate rainfall at high altitudes. Different intra-annual tree growth patterns could be identified within each elevational forest type, showing species with strictly seasonal growth, continuous growth or alternating growth patterns independent of the seasons. Stem growth at each site was generally larger during rainy seasons, except for the elfin forest. The rainy season from October 2013 to March 2014 was extraordinarily dry, with only 73% of long-term mean precipitation received, which resulted in reduced radial growth, again with the exception of the elfin forest. This indicates that montane tropical rain forests may suffer from prolonged droughts, while exposed ridges with elfin forests still receive plenty of precipitation and benefit from receiving more solar radiation for photosynthesis. 相似文献
11.
Concentrations of Pb in individual stem xylem rings of 5-year-old Norway spruce trees (Picea abies (L.) Karst.) were determined after one growing season in soil containing a low, medium or high concentration of Pb. In trees in the control and low-Pb soil treatments, Pb concentrations increased from the outer annual rings toward the stem center, whereas in trees grown in the soil treatment containing a medium Pb concentration, all of the four tree rings analyzed contained similar concentrations of Pb. Although trees grown in the high-Pb soil treatment had higher concentrations of Pb in the outer annual rings than both control trees and trees in the low-Pb soil treatment, the highest concentrations of Pb were never observed in the outermost rings, which were formed during the period of exposure to increased soil Pb. We conclude that radial distribution patterns of Pb in Norway spruce stems do not directly reflect changes in soil Pb concentration but depend on several internal, physiological factors and, therefore, do not provide reliable information about past variations in Pb contamination of soil. 相似文献
12.
Silpi U Thaler P Kasemsap P Lacointe A Chantuma A Adam B Gohet E Thaniswanyankura S Améglio T 《Tree physiology》2006,26(12):1579-1587
Rubber tree (Hevea brasiliensis Müll. Arg.) radial growth dynamics were monitored with displacement sensors, together with latex production, to investigate three aspects of the dual production of latex and wood: (1) the usefulness of fine-scale dendrometric measurements as a physiological tool to detect water shortage through radial growth; (2) the dynamic aspects, both at the seasonal and at the multi-year scale, of the competition between latex and wood production; and (3) the spatial distribution of radial growth rates around the tapping cut. Radial growth of untapped control trees started with the onset of the rainy season and lasted until the onset of the dry season, ceasing completely during the driest period. Displacement sensors provided a sensitive means of detecting water shortage, with a clear correlation between diameter variations and changes in water availability (both daily evapotranspiration and monthly rainfall) over the whole annual cycle. However, the correlation was significantly disturbed in tapped trees. After resumption of tapping, the radial growth rate dropped sharply within two weeks and the effect persisted throughout the whole season, so that the cumulative growth of tapped trees was about half that of untapped trees, with the cumulative growth deficit reaching 80% for the period from mid-June to November. This long-known negative impact of tapping on growth was much stronger in the second year of tapping than in the first, whereas latex production increased significantly between the first and second year of tapping. The increased latex production, which could not be ascribed to climatic conditions, shows that the establishment of an artificial latex sink is a progressive, long-term process likely involving many aspects of metabolism. As expected, ethylene significantly increased latex production in both years; however, ethylene had no effect on the growth rates of tapped trees. Radial growth was differentially affected at different locations around the tapping cut, with growth rates significantly lower in the tapped panel than in the untapped panel, and higher above the cut than below the cut. Thus, caution is needed when deriving whole stem wood production from girth measurements at one location on the stem, especially from girth measurements made close to the tapping cut. This also provides new evidence for the location of the latex regeneration area in the tapped panel, below the cut. 相似文献
13.
Andreas Gruber Jolanda Zimmermann Gerhard Wieser Walter Oberhuber 《Annals of Forest Science》2009,66(5):503-503
14.
Wood density affects the strength of lumber and paper products. Despite considerable research, however, the key factors influencing wood density are still not fully understood. The aim of this study was to analyze the effects of variables within and among trees on the density of current wood growth along the stem in order to further understanding and prediction of wood quality. Correlation analyses together with linear mixed effects and randomForest modelling were carried out using stem analysis and tree-level data from long-term balsam fir and white spruce stand density experiments in Eastern Canada. Wood density showed highly structured patterns of variation among trees. Mixed effects and randomForest models, which incorporated tree-level effects accounted for much of the wood density variation. The three most influential variables identified by randomForest analysis for both species were tree slenderness, relative height and ring width. Wood density increased with slenderness and relative height, and these variables affected relationships of wood density to ring width. Wood density is associated with interacting variables within and among trees including tree slenderness and relative height. Wood density is related to ring width, but this relationship is modulated by tree-level influences which likely reflect mechanical stability requirements. 相似文献
15.
The progress of xylem formation in Norway spruce (Picea abies (L.) Karst.) was measured during one growing season in southern Finland. Stem radius was monitored continuously with band dendrometers, and the formation of new tracheids was determined by examination of small increment cores taken twice weekly. Tracheid production started in June and ceased in August. Xylem formation was fastest in early July, when 0.75-1.25 new tracheids were formed per day. The rate of xylem formation was significantly correlated with mean daily temperature. Synchronous fluctuations in tracheid and lumen diameters were observed at the same relative positions within each annual ring, but no relationship existed between the diameters and weather variables. The timing of changes in stem radius differed from the timing of actual xylem formation. Stem radius increased in April and May, and the fastest daily increments were recorded in June. Increases in stem radius slowed in July, but small increases were measured more than a month after xylem formation had ceased. Daily changes in stem radius were correlated with daily precipitation, reflecting changes in stem water content. Therefore, dendrometers are of dubious value for measuring the timing of actual xylem formation. Small increment cores proved to be useful in assessing actual xylem formation, but the method is laborious. 相似文献
16.
G. Lesnino 《Wood Science and Technology》1994,28(2):159-171
Summary For the assessment of many different aspects of growth processes in trees millions of annual rings are being measured all over the world every year. Other studies dealing with the prediction or explanation of wood properties also require numerous density measurements. While the density of a wood sample is relatively easy to determine by stereogravimetric methods, density relationships or variations within a piece of wood and within individual annual rings can only be detected by time-consuming techniques, e.g. radiodensitometry. A new, simplified method for ring analysis was developed with the aid of the sandblasting and laser sensor method. This process permits the automatic recording of annual radial increment and simultaneously provides results on the mean and intra-annual density of the wood specimens. Sandblasting of cross-sections of stems or of radial strips produces hardness profiles. Due to the hardness variations in these profiles individual annual rings can be more or less easily identified macroscopically, depending on the wood species. Furthermore, density variations are also macroscopically visible on account of the relationship between abrasion depth and density: Sandblasting can be said to provide a three-dimensional representation of the density relationships in wood. Following the numerical recording of these surface profiles with the aid of a laser sensor and upon conversion of abrasion depth profiles into density profiles radial increment and density parameters for stem radii, segments of radii or even individual annual rings can be determined. A comparison with the conventional radiodensitometric ring analysis method shows very good correlations with the results achieved in this study. The advantage of the laser-sandblasting method is that large samples can be investigated without great preparatory effort and in a single processing step. 相似文献
17.
Katrin P. Zimmer Olav A. Høibø Geir I. Vestøl Erik Larnøy 《Wood Science and Technology》2014,48(5):1049-1068
The treatability of Scots pine sapwood sampled from 25 locations in northern Europe, which was impregnated with an experimental furfuryl alcohol mix, was studied. A large variation in treatability was found between stands. The treatability was affected by anatomical properties of the trees and therefore also by the immediate climate, the sociological position of the tree in the stand, growth increments and on-stand competition. With the models applied, most parts of the differences in treatability between stands could be explained, while the treatability variation between trees within a stand remained mostly unexplained. Wider annual rings and higher latewood contents were found to increase the treatability. Models that included data on growth conditions and climate explain more of the variation in treatability, indicating that also other anatomical properties are influencing the treatability. Tree attributes and growth conditions that reduce annual ring width and latewood content decreased the treatability. Trees growing under warmer conditions and developing larger growth increments were easier to impregnate. Wood from trees growing near the timberline and under environmental conditions impairing wood growth was more difficult to treat. 相似文献
18.
《Southern Forests》2013,75(3-4):191-200
Many eucalypt species do not show distinct growth rings because cambial activity does not show a strong response to seasonal variation in climate. Eucalyptus grandis, one of the most important commercial hardwood species in South Africa, is one such example of a species that does not have well-defined growth rings. The light and dark bands visible on the cross-section of the wood of E. grandis do not always correspond with the growing season, which makes it difficult to resolve wood property data into annual increments. A method was developed to separate growth rings on wood density profiles of E. grandis into annual increments using bark-to-pith density profiles and annual measurements of diameter at breast height (DBH) from permanent sample plot (PSP) datasets. Using the PSP data, it was possible to assess the annual pattern of stem diameter growth at a compartment level by calculating the radial increment (RI) per year and expressing that value as a percentage of the radius at the end of the increment for that year. Mean radial increment percentage (%MRI) was calculated for each year and used to predict annual RI at an individual tree level. Predicted RI values for each tree were expressed as cumulative distances from the bark end and superimposed onto their respective density profiles. Predicted RI corresponded well with latewood density peaks and these separation points were considered a reliable guide to divide the density profile into annual increments closer to the bark end and into broader age classes closer to the pith. By assessing the pattern of variation in radial density within the context of the growth history of a compartment by means of annual PSP data, it was possible to confirm that growth rings on density profiles of E. grandis closer to the bark end can serve as a reliable representation of annual growth. 相似文献
19.
The influences of cambial age and ring width on density of Sitkaspruce (Picea sitchensis (Bong.) Carr) were analysed in relationto within-tree trends in tracheid diameter and cell wall thickness.Discs were sampled at breast height from a total of 24 trees,from seven stands at three contrasting sites in Wales, and atbreast height, 30 per cent and 60 per cent total tree heightfrom one of the stands. Across the juvenile wood, ring density decreased with ring numberfrom the pith while radial tracheid diameter increased. Theseoverall trends were considered to be inherent to tree growth,presumably associated with cambial ageing, since they occurredin all trees on all sites. In juvenile wood, density also variedwith site growth rate (as indicated by ring width) at similarcambial age, wider rings being associated with more rapidrateof change in tracheid diameter with ring number and with decreasein tracheid wall thickness. Consequently, on a site having treeswith high growth rate density decreased more rapidly acrossthe juvenile wood, down to a lower minimum value, than on siteswith a slower growth rate. In mature wood, the decrease in densitywith increase in ring width was associated with differencesin both tracheid diameter and wall thickness. Density was slightly(though not significantly) higher at breast height than in comparablerings at 30 per cent total height, associated with significantlythicker tracheid walls at breast height. Changes in radial tracheid diameter (with ring number, or withring width) were associated with greater differences in theearlywood than towards the latewood end of each growth ring,while variations in wall thickness with ring width were associatedwith rate of increase in wall thickness towards the latewoodend. This may account for some previously conflicting reportson influence of silvicultural management on density, for densityis likely to vary with influence of environment on the seasonalcycle of cambial activity. The extent of the juvenile wood as delimited by the inner coreof wide growth rings does not necessarily correspond to theregion of varying tracheid dimensions in Sitka spruce. 相似文献
20.
Veli-Pekka Ikonen Heli Peltola Lars Wilhelmsson Antti Kilpelinen Hannu Visnen Tuula Nuutinen Seppo Kellomki 《Forest Ecology and Management》2008,256(6):1356-1371
In this work, empirical ring-based models were developed to predict the distribution of early wood percentage, wood density and fibre length along the stems of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) as affected by silvicultural management. The performance of the ring-based models was also compared for Scots pine and Norway spruce with corresponding disc-based (cross-sectional) models. Moreover, both models were integrated with example simulations by a process-based growth and yield model to analyze how management, such as thinning, affects the growth and wood properties of Scots pine trees over a rotation as an average for the tree stem, but also along the stem.The ring-based models built for annual early wood percentage (explained by ring width), air dry wood density (explained by early wood percentage and cambial age) and fibre length (explained by radial growth percentage and cambial age) predicted reasonably well the wood properties both at an intra-ring level, but also at a cross-sectional level. These predictions were also reasonably well in line with corresponding cross-sectional predictions by the disc-based models (which predicted the properties based on the number of annual rings and diameter at breast height and/or the cross-section being considered and temperature sum). The example simulations also demonstrated that both models predicted slightly lower wood density for dominant trees compared to dominated ones grown in thinned and unthinned Scots pine stands over a rotation. Unlike the disc-based model, the ring-based model predicted, on average, higher early wood percentage in dominant trees than in dominated ones. However, fibre length was not significantly affected when the averages of the whole stems were predicted, and this held true for both ring- and disc-based models.In summary, the incorporation of empirical ring-based wood property models into a process-based growth and yield model, offers a means to study in detail how environmental conditions, forest structure and management affect the quantity and properties of stem wood produced over a rotation. The disc-based wood property models used in this work are based on data with large geographical and genetic variation, and therefore may turn out to be more applicable for predicting future wood and fibre resources at a regional and national level. This kind of integrated use of wood property models with a process-based growth and yield model could help us to evaluate the forest resources under current and changing climate. 相似文献