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红豆树截干时间和截干高度对穗条生长的影响 总被引：2，自引：0，他引：2
对红豆树2年生容器苗进行截干促萌试验,分析截干时间和截干高度对穗条生长的影响。结果表明:截干时间明显影响穗条长度和穗条直径。相对3月而言,11月和1月截干的植株穗条较长,直径明显较粗,2者对应长度和直径分别为44.79,44.28 cm和6.91,6.75 cm,均高出3月对应指标15%,且此2时间节点的穗条性状不存在明显差异;截干高度对穗条长度的影响亦较为显著,截干高度15 cm植株穗条最长,达44.58 cm,与截干高度5 cm处理所致穗条长度间差异不显著,但显著长于截干高度30 cm的植株穗条。不同截干时间节点的截干高度对穗条生长的影响不一致,11月和1月,截干高度为15,30 cm的植株,萌发穗条数量显著多于截干高度为5 cm的植株;3月,则表现出截干高度愈高穗条长度愈长的现象。因此,在树液流动前,对红豆树进行截干较为理想;15 cm是较理想的截干高度,截干高度较高,对获得穗条数量影响不大。 相似文献
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《福建林业科技》2021,(3)
对种植1 a后的多穗柯林分采用不同高度截干处理(分别在主干离地面10、30、100 cm处截干),以不截干自然生长为对照(CK),研究不同高度截干处理对多穗柯分枝率、枝长度、分枝角、枝径比等指标的影响。研究结果表明:截干处理后,枝构型发生了一定程度的变化,不同处理间存在差异。截干处理使树高降低,总分枝率显著低于对照,逐级分枝则极显著或显著高于对照,总体分枝长度提高,分枝角变小。除第2级枝级直径与第1枝级直径的比率(RBD_(2∶1))为对照处理最大外,其它各级枝径比均为截干处理大于对照。不同截干高度间,随着截干高度降低,差异化程度渐大。以在主干离地面10 cm处截干处理为最优。总体上截干处理分枝能力增强,末级分枝数量较多,有利于多穗柯矮化密植。 相似文献
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《林业实用技术》2021,(8):60-63
以落叶松种子园大龄母树为研究对象,对其进行截干试验,对比分析不同截干高度和不同截面处理对落叶松种子园母树枝条萌发和生长的影响。结果表明,不同截干高度对枝条萌发簇数、枝条总数、枝长和枝基径的影响极显著,截干高度为3 m的树干平均枝条萌发簇数、枝条总数、枝长和枝基径生长量均最大,其次是截干高度为2 m,截干高度为1 m的树干最小,在最佳A处理下,截干3 m的平均枝条萌发簇数、枝条总数、枝长和枝基径分别为8.3簇、44.3条、43 cm和0.53 cm,分别是截干1 m的6.25倍、4.75倍、3.07倍和2.86倍;不同截面处理对萌枝长、萌枝条总数和枝基径的影响达显著或极显著差异,不同截面处理对树干枝条萌发簇数、枝条总数、枝长和枝基径的影响从大到小依次为A处理(断面涂抹铅油处理)D处理(断面涂抹伤口愈合剂)C处理(断面涂抹铅油处理后,外包塑料布)B处理(用ABT生根粉处理后,外包塑料布),A处理的树干枝条萌发簇数、枝条总数、枝长和枝基径分别为8.3簇、44.3条、43 cm和0.53 cm,分别是B处理的2.78倍、12.09倍、2.92倍、1.62倍。本研究表明,截干高度3 m,断面涂抹铅油处理是落叶松种子园大龄母树截干最佳处理方式,采用这种处理方式更有利于促进树干隐芽萌发。本研究结果对于提高初级落叶松种子园大龄母树产种能力,改善种子品质具有重要的借鉴意义。 相似文献
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截杆处理对大龄杉木种子园种子产量与品质的影响研究 总被引：2，自引：0，他引：2
《西部林业科学》2015,(2)
以杉木种子园大龄母树为研究对象,对其进行截杆试验,对比分析截杆与未截杆处理对母树球果产量、球果大小、种子产量、种子质量以及种子发芽能力的影响。结果表明,截杆处理对大部分无性系母树种子产量、种子质量以及种子发芽能力均具有显著的促进作用。截杆处理对球果产量指标影响不显著,但截杆后球果鲜重和干重的综合增益值均在60%以上;单株种子重、出籽率、种子千粒重和优良度的综合增益值分别为104.23%、33.90%、17.08%和82.72%;种子发芽率、发芽势和发芽指数的综合增益值分别为130.32%、134.41%、133.28%。说明截杆处理可提高母树种子产量和质量,且可显著提升种子的发芽能力,提高种子发芽率和整齐度,缩短种子发芽时间。 相似文献
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Kristina Ahnlund Ulvcrona Thomas Ulvcrona Urban Nilsson Tomas Lundmark 《Scandinavian Journal of Forest Research》2014,29(3):197-209
The increasing demand for forest biomass for energy generation could be partially met by growing denser stands and use of fertilizer. Before this is done at large scale, more knowledge of the effects of stand density and fertilization on aboveground allocation patterns and stem form is needed. Therefore, effects of pre-commercial thinning (PCT) to 3000 stems ha?1, an unthinned dense control (C), and PCT combined with two levels of fertilization (100 kg ha?1 of nitrogen applied either during the establishment of the field experiment (F1) or annually (F2)) were examined in 23- to 26-year-old Scots pine (Pinus sylvestris L.) stands six years after the establishment of the field experiment. In total, 114 sample trees were harvested using destructive biomass sampling. The growth allocation and stem form of trees with diameter at breast height (DBH; 1.3 m height) >5.0 cm were not affected by either the PCT or fertilization. Small trees (DBH < 5 cm) in denser, unthinned control plots had more slender stems (lower DBH/height ratios) and allocated less growth to branches and foliage than trees in PCT plots. Fertilization had little effect on the stem form and growth allocation of the smallest trees. Therefore, effects of stem density and fertilization on stem form and growth allocation to foliage were only found for small suppressed trees, and the treatments had very little influence on dominant and codominant trees. 相似文献
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A forest biomass yield table based on an empirical model 总被引：1，自引：0，他引：1
Tomohiro Nishizono Toshio Iehara Hirofumi Kuboyama Miki Fukuda 《Journal of Forest Research》2005,10(3):211-220
We report an empirical model for estimating unutilized wood biomass, and its application to Cryptomeria japonica D. Don and Larix kaempferi in Tohno City, Iwate Prefecture, northeast Japan. Outputs from the model are the quantity of unutilized wood biomass and merchantable volume produced by timber harvest. The unutilized wood biomass is divided into stumps, tops, branches, foliages, small trees, and unutilized stems due to their defects. Inputs to the model are mean diameter at breast height (DBH), mean tree height, trees per unit area, and timber utilization standards. DBH distribution, DBH–height curve, stem form, bark thickness, and relationship of stem biomass to foliage and branch biomass could be described by the proposed model, indicating its validity. The proposed model enables us to develop the forest biomass yield tables modified from the existing stem volume yield tables. The developed forest biomass yield tables indicated that the unutilized wood biomass due to defects accounted for the largest part of the whole unutilized wood biomass, and that the ratio of unutilized parts in stem volume to total stem volume could vary with stand age and site productivity class. Based on a comparison of the developed forest biomass yield tables with those reported previously, we concluded that the proposed model-based forest biomass yield table would be useful for estimating the quantity of unutilized wood biomass. 相似文献
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Philip J. Radtke Ralph L. Amateis Stephen P. Prisley Carolyn A. Copenheaver David C. Chojnacky Judd R. Pittman Harold E. Burkhart 《Forest Ecology and Management》2009
Forest management can have large impacts on the production and yield of coarse woody debris (CWD) in terrestrial ecosystems, yet few modeling tools exist to inform such efforts. The goal here was to develop a set of prediction equations for use in conjunction with loblolly pine (Pinus taeda L.) modeling and inventory systems to estimate CWD yields at scales ranging from individual trees to whole plantations. Permanent field plots from a 21-year study of thinning effects on plantation growth and yield across the commercial range of the species in the southern United States were surveyed to obtain sample data on CWD volume, density, and mass. Measured CWD properties were combined with inventory records of tree mortality over the study duration to characterize CWD production, decay and yield in a series of prediction equations. The resulting equations predict CWD attributes of dead trees including dry weight (kg) and fraction of standing versus downed woody material based on the time since death (years), tree diameter at breast height (cm) and height (m) at time of death and geographic coordinates of latitude and longitude. A stand-level equation predicts total CWD yield (Mg ha−1) for thinned or unthinned stands based on plantation age, stem density (trees ha−1), and the average height of dominant and codominant trees (m). Piece-level equations predict dry density (kg m−3) or nitrogen concentration (%) of CWD pieces based on their position (standing or down), ordinal decay classes, and latitude. The tree and stand-level prediction equations are designed for use in GIS or growth and yield modeling systems. The piece-level equations are designed to be used in inventory applications that survey CWD. The equations should facilitate the accurate and facile determination of mass, carbon, and nitrogen contents of CWD in planted loblolly pine forests of the southern United States. 相似文献
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对湖南省东安县杉木无性系种子园母树的生长结实性状进行定点观察和综合分析，结果表明，不同地理种源球果产量的差异，均未达到统计上的显著水平．但在不同无性系间，存在显著的差异：树高和胸经在种源和无性系间均存在显著差异，冠幅仅在无性系间有差异，枝下高差异不明显；树高、冠幅与球果呈极显著相关．胸经与球果呈显著相关，枝下高与球果相关不明显．偏北种源较偏南种源球果产量高．种源和无性系的球果重复力偏低．据此，对种子园的营建和经营管理，提出了有益的建议和讨论 相似文献
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This study considered the effects of thinning on the development of compression wood in stems of 35-year-old stand of Corsican
pine (Pinus nigra L.). Part of the stand had been thinned at 5-yearly intervals and part left unthinned. Twenty trees each from the thinned
and unthinned stands were randomly selected and felled. Measurements were made on tree height, stem diameter, stem slenderness
and canopy depth. Wood samples were removed from the central part of the main log and cross-sectional measurements made on
ring width, basic density and compression wood content. Cross-sectional area of compression wood was found to be three time
higher in stems from the unthinned trees in comparison with those from the thinned trees. No significant differences in mean
radial ring width or basic density were found between treatments. Correlations indicated that, with increasing in stem diameter,
compression wood content increased in the unthinned trees, while a decline in compression was observed in the thinned trees.
Tree height was also positively correlated with compression wood content in unthinned trees, while no equivalent relationship
was observed in thinned trees. Observations from this study, while not conclusive, suggest that phototropic stimulus may be
producing stem inclinations in the unthinned stand as trees compete for space in the canopy, whereas crown competition has
been largely eliminated in the thinned stand; and that this is responsible for compression wood levels recorded in this study. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1-4):121-126
The aim of the study was to develop methods for estimating the taper curves for trees tallied in a forest inventory. The average stem form in a stand was described by the principal components of the stand effects in the stem dimensions measured in the polar coordinate system. Measurements of diameter at breast height, diameter at a height of 6 meters, and height taken from trees on the sample tree plots were used for determining the first four principal components. Regression models were derived to predict the principal components from the site and growing stock variables. These models were used to estimate the taper curves of the tallied trees. Use of the principal components estimated by the regression models gave less reliable results than use of the principal component estimates based on measurement of the height of one randomly chosen tree on the sample plot. The best result was found with combined use of the principal component estimates and one height measurement per sample plot. 相似文献
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北京栓皮栎林分的干形质量初步研究 总被引：2，自引：0，他引：2
探讨了划分林木干形质量的标准,将林木干形质量分为通直、轻度弯曲、二杈分枝、多杈分枝和重度弯曲5类干形。选择了胸径、树高、冠幅、冠长等6个因子,并研究了这6个调查因子随干形质量变化的关系。通过方差分析发现不同干形质量的林木胸径差异并不明显,而其它的调查因子却因干形不同而表现出显著差异。对表现显著的林分因子进行多重比较研究,发现通直干形生长得较高、有较小的冠径比;二杈分枝和多杈分枝林木的冠幅较大,且二杈分枝类型林木的高径比最小。可以得出结论:在近自然经营过程中,在选择以材质为目的的目标树时,首先考虑干形通直的林木。 相似文献
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The long term effects of superphosphate fertilization on stem form, taper and stem volume estimation of Pinus radiata on a phosphorus-deficient site was examined using data from a fertilizer experiment which had been maintained for 30 years. The application of superphosphate resulted in long term and statistically significant changes in stem form. Mean cylindrical form factor ranged from 0.33 for the control trees up to 0.40 for trees fertilized with 100 kg P ha−1. Stem form was also examined through taper curves which provided detailed depiction of average relative stem profiles. The increase in cylindrical form factor of fertilized trees was largely attributed to a significantly broader profile of the lower third of the stem. In comparison with the control trees, the fertilized trees also had a broader, although not statistically significant, profile of upper and middle stem which could also contribute to the increase in their cylindrical form factor. With increased form factor a greater proportion of the stem became merchantable because of increased log length to tree height ratio. Mean average taper of trees did not show a consistent trend with increasing lelevels of superphosphate application. It largely reflected the differential response of DBH and height growth to the treatments. The volume equation based on control trees underestimated the underbark stem volume of fertilized trees by 5–12% on average. Developing separate volume equations for the fertilized trees is warranted. 相似文献
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We studied effects of tree age, size and competitive status on foliage and stem production of 43 Scots pine (Pinus sylvestris L.) trees in southern Finland. The tree attributes related to competition included foliage density, crown ratio and height/diameter ratio. Needle mass was considered to be the primary cause of growth through photosynthesis. Both stem growth and foliage growth were strongly correlated with foliage mass. Consequently, differences in growth allocation between needles and stem wood in trees of different age, size, or position were small. However, increasing relative height increased the sum of stem growth and foliage growth per unit foliage mass, indicating an effect of available light. Suppressed trees seemed to allocate more growth to stem wood than dominant trees, and their stem growth per unit foliage mass was larger. Similarly, trees in dense stands allocated more growth to stem wood than trees in sparse stands. The results conformed to the pipe model theory but seemed to contradict the priority principle of allocation. 相似文献
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Root architecture in relation to tree-soil-crop interactions and shoot pruning in agroforestry 总被引：7，自引：0，他引：7
Desirable root architecture for trees differs between sequential and simultaneous agroforestry systems. In sequential systems extensive tree root development may enhance nutrient capture and transfer to subsequent crops via organic pools. In simultaneous systems tree root development in the crop root zone leads to competition for resources.Fractal branching models provide relationships between proximal root diameter, close to the tree stem, and total root length or surface area. The main assumption is that a root branching proportionality factor is independent of root diameter. This was tested in a survey of 18 multipurpose trees growing on an acid soil in Lampung (Indonesia). The assumption appeared valid for all trees tested, for stems as well as roots. The proportionality factor showed a larger variability in roots than in stems and the effects of this variabilily should be further investigated. A simple index of tree root shallowness is proposed as indicator of tree root competitiveness, based on superficial roots and stem diameter.Pruning trees is a major way to benefit from tree products and at the same time reduce above-ground competition between trees and crops. It may have negative effects, however, on root distribution and enhance below-ground competition. In an experiment with five tree species, a lower height of stem pruning led to a larger number of superficial roots of smaller diameter, but had no effect on shoot:root ratios or the relative importance of the tap root. 相似文献