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为探究橡胶树与白木香混交种植方式对白木香幼林苗木生长的影响,选用3块不同郁闭度的橡胶林地为试验区,采用4种种植模式对白木香进行造林,调查造林后3～12个月间白木香幼林苗木生长状况。调查结果显示：不同试验区的种植模式三白木香幼林苗木苗高、地径、冠幅生长速度较其他种植模式快。高郁闭度橡胶林分下,白木香幼林苗木苗高、地径、冠幅生长显著不及低郁闭度林分下种植的白木香幼林苗木。研究表明,白木香幼林苗可在橡胶林下正常生长,且在低郁闭度橡胶林分下,白木香幼林苗种植株行距为2.0m×1.0m、白木香与橡胶树相距2.5 m的种植环境对白木香幼林苗生长更有利。 相似文献
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采用L9（34）正交设计,探讨了不同营林措施对云南石梓幼林生长的影响。结果表明：造林整地方式对4年生云南石梓幼林生长的影响最大,其次为锄草松土次数和造林初植密度。云南石梓幼林胸径、树高生长的最优组合为造林初植密度1111株／hm2、水平阶整地,带宽1 m,再挖定植穴40 cm ×40 cm ×40 cm、每年锄草松土4次;冠幅生长以造林初植密度816株／hm2、定植穴50 cm ×50 cm ×50 cm、每年锄草松土3次组合效果最佳。 相似文献
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为探寻闽南山地灰木莲的合理种植密度,以促进林分高效生长,在闽南山地开展灰木莲6种不同初植密度试验,分析比较不同初植密度对5 a生幼林生长及形质性状的影响效应,结果表明：种植密度对灰木莲的幼林生长和形质性状存在显著性影响,种植密度越大,树高、胸径、枝下高、主干分叉性、侧枝密度、侧枝角度等性状表现越好,而种植密度对冠幅、主干通直度、侧枝粗细等性状无显著性影响。综合各项生长指标效应,灰木莲适宜的初植密度为1 667～3 333株·hm-2(株行距1.5 m×2.0 m和2.0 m×3.0 m),能有效促进灰木莲快速生长以及形成较好的形质性状。 相似文献
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《福建林业科技》2020,(2)
2016年在福建省龙海林下国有林场,采用从泰国等引进的交趾黄檀26个家系的营养袋苗,进行引种造林试验,2019年对其胸径、树高、冠幅和保存率指标作统计分析。结果表明:4年生交趾黄檀不同家系间幼林生长差异达显著或极显著水平,平均胸径4.3 cm、树高4.89 m、冠幅2.62 m、保存率95.82%;表现最优的家系为13号,平均胸径5.3 cm、树高5.44 m、冠幅3.02 m,分别比林分平均值增加23.3%、11.2%、15.3%。根据胸径、树高生长量2个指标,用隶属函数法初步选出5个幼林期生长表现较好的家系(13、22、2、18、15号),可为交趾黄檀的引种与栽培提供参考。 相似文献
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【目的】通过分析不同混交模式下马尾松及格木生长量差异,探讨马尾松与格木混交的适宜模式,为马尾松格木混交林的营建提供理论基础。【方法】以广西凭祥5年生马尾松和格木人工林为研究对象,分析不同混交模式及混交比例马尾松和格木的胸径、树高、冠幅及材积的差异,探寻马尾松格木混交合理的混交模式和混交比例。【结果】1)不同混交模式马尾松胸径、树高、冠幅和材积均差异显著。处理a和CK3林分平均胸径最大,均为5.9 cm,CK3林分平均树高、上下冠幅和左右冠幅最大,分别为4.9、2.4和2.7 m。CK3的单株材积最大为0.0082 m3,处理c林分平均胸径、平均树高和单株材积均最小,分别为5.0 cm、4.1 m和0.0051 m3,同时上下冠幅和左右冠幅最小,分别为2.0 m和2.1 m。2)不同混交模式格木胸径、树高、冠幅和材积均差异显著。CK2林分平均胸径最大为5.1 cm,最小为处理c的4.1 cm。处理a和CK1林分平均树高最高,均为4.8 m,处理c树高最低为4.0 m。处理a、处理b和CK2上下冠幅最大,均为2.4 m,处理c上下冠幅最小为2.0 m,CK1左右冠幅最大为2.8 m,处理c左右冠幅最小为2.1 m。CK2格木单株材积最大为0.0058 m3,处理c单株材积最小为0.0035 m3。3)不同的混交模式和混交比例不影响径级数量的分布规律,各处理及对照中马尾松和格木的径级均呈正态分布。【结论】马尾松与格木幼林4种混交模式在胸径、树高、冠幅和材积均存在显著差异,马尾松与格木(75丛·hm^-2)各项生长指标相对较优,其次为马尾松+格木(4:1)行状混交,生长表现最差为马尾松+格木(210丛·hm^-2)。综合考虑,以培育马尾松大径材为经营目标,早期应选择马尾松与格木(75丛·hm^-2)模式进行混交。 相似文献
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油茶新造幼林挂果特性及其产量测定 总被引：1，自引：1，他引：0
通过10多a的连续观测研究,发现油茶新造幼林第2～3年可以开花结果,第4、5年的挂果率达到47．4%～62．3%,单株产果量,单株冠幅和冠幅产果量均呈逐渐递增的趋势．造林后第8～10年进入盛果期．分析了油茶新造幼林挂果的特点和开花结实规律,提出了油茶新造幼林产量测定的基本方法和标准．油茶新造幼林的产量测定以冠幅面积产果量推算时,从第5年开始,连续4a测定单株产果量和单株冠幅,计算平均每m~2冠幅产果量,再按盛果期郁闭度为0．60时的结果冠幅面积来推算油茶成林盛果期的单位面积产量较为适宜,然后根据历年取样测定的鲜果含油率来计算产油量． 相似文献
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Twenty-year-old overstocked naturally regenerated yellow birch (Betula alleghaniensis Britton) were thinned near Thessalon, Ontario. Treatments consisted of either a control, or the removal of all competing trees at 1, 2, 3, or 4 m around the boles of the crop trees. The size of the openings created around the crop tree crowns was found to be more strongly correlated to diameter, clear bole length, and crown increment than the removal of competing trees using fixed distance from the stem. Crop trees responded well to thinning. Five-year diameter increment and crown diameter growth were positively correlated to size of the opening created around the crop tree crown. However, the relationship between height growth and size of canopy opening was weak. Clear bole length was found to be negatively correlated to the size of canopy opening. Few epicormic sprouts developed on the stems when all competing trees were removed at 1, 2, or 3 m around the crop tree boles. However, release at 4 m greatly increased the number and size of epicormic sprouts. Providing about a 15-m2 opening around the crop tree crown, corresponding to approximately a 3-m removal of competing trees around the bole, provided a good balance between diameter increment and stem quality maintenance. 相似文献
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Shufang Yu Jim L. Chambers Zhenmin Tang James P. Barnett 《Forest Ecology and Management》2003,180(1-3):345-352
Total foliage dry mass and leaf area at the canopy hierarchical level of needle, shoot, branch and crown were measured in 48 trees harvested from a 14-year-old loblolly pine (Pinus taeda L.) plantation, six growing seasons after thinning and fertilization treatments.
In the unthinned treatment, upper crown needles were heavier and had more leaf area than lower crown needles. Branch- and crown-level leaf area of the thinned trees increased 91 and 109%, respectively, and whole-crown foliage biomass doubled. The increased crown leaf area was a result of more live branches and foliated shoots and larger branch sizes in the thinned treatment. Branch leaf area increased with increasing crown depth from the top to the mid-crown and decreased towards the base of the crown. Thinning stimulated foliage growth chiefly in the lower crown. At the same crown depth in the lower crown, branch leaf area was greater in the thinned treatment than in the unthinned treatment. Maximum leaf area per branch was located nearly 3–4 m below the top of the crown in the unthinned treatment and 4–5 m in the thinned treatment. Leaf area of the thinned-treatment trees increased 70% in the upper crown and 130% in the lower crown. Fertilization enhanced needle size and leaf area in the upper crown, but had no effect on leaf area and other variables at the shoot, branch and crown level. We conclude that the thinning-induced increase in light penetration within the canopy leads to increased branch size and crown leaf area. However, the branch and crown attributes have little response to fertilization and its interaction with thinning. 相似文献
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We tested hypotheses on the effect of growing space and biomechanics on tree growth, using data from two field experiments where Scots pine seedlings had been planted in a fixed but systematically irregular pattern. After 16 or 18 years, respectively, stem diameter was measured at 1.3 m (d1.3) and 0.3 m above ground (d0.3). Total tree height, length and diameter of the crown, and height to crown gravity point were also measured. Analyses were split in two parts: influence of growing space on tree and crown dimensions, and biomechanical influence of the crown on stem diameter. The results showed that crown size was closely related to tree height, and that there was a small but statistically significant effect of growing space on both crown size and shape. The biomechanical model explained about 85% of the variation in stem diameter, but growing space had no influence on this relationship, indicating that the wind load absorbed by a given crown size was not affected by growing space. The results were discussed in relation to future growth modelling and new ways of estimating site productivity. 相似文献
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早熟矮化丰产稳产板栗新品种——农大1号及其栽培技术 总被引：2，自引：0，他引：2
农大１号板栗是由阳山油栗经辐射诱变而选育的板栗新品种,具早熟、矮化、丰产稳产等优良性状。成熟期８月下旬至９月上旬;８年生平均树高３．３ｍ,冠幅２．７ｍ,平均株产２．８ｋｇ,最高株产１０．７ｋｇ,果实品质优良,性状稳定。并根据农大１号的特点提出了栽培技术措施及其应用前景 相似文献
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文章采取典型样地调查的方法,对不同带间距对柠条林的影响进行研究,结果如下:①柠条灌丛生长中冠幅、树高、新梢的相关性较强,各带间距林地柠条3个生长指标排序均为:2m>16m>8m>4m;丛径排序均为:2m>4m>8m>16m;枝条数量排序均为:4m>8m>2m>16m。②2m、4m、8m、16m带间距林地一年生枝叶与多年生枝的比例依次为3∶7、1∶9、3.4∶6.4、4∶6,8m和16m带间距林地柠条的饲用价值更为突出。③4m、8m带间距林地土壤含水量接近,且垂直分布较均匀,好于2m、16m带间距林地。④随带间距增加风速和湿度增加,温度下降;2m带间距林地作用较明显,其他3种林地则作用相似。⑤4m、8m带间距林地优质牧草重要值占总值的51.79%~43.03%之间,多年生植物重要值占总值的1/3左右,好于2m、16m带间距林地。⑥柠条林带间植物多样性指数排序为:16m>4m>8m>2m,丰富度指数排序为:2m>8m>4m>16m,均匀度指数排序为:2m>8m>4m>16m。⑦综合柠条生长情况、带间植物重要值和多样性指标、林地土壤水分和林地对小气候的调控作用,4m、8m带间距林地在研究地是比较适合的造林模式。 相似文献
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秦岭森林潜在火行为数量分类及划分指标研究 总被引：4，自引：0，他引：4
根据秦岭林区 4 5块标准地和 2 2 5个样方的冠层易燃物最大密度 (D)、地表可燃物载量 (W )及地表可燃物绝对含水率 ( μ) 3个实测值的 1 35个数据 ,运用Dissimilarityanalysis计算认为 ,调查的 4 5块标准地明显地可聚为 6类。据类间差异性将秦岭森林潜在树冠火行为分为强度树冠火、弱度树冠火和无树冠火 3种类型 ,划分依据为冠层易燃物最大密度 ,区分指标分别为 0 1 1kg/m3 和 0 37kg/m3;地表火强度划分应用μ和W 双因素判断法 ,并将其划分为强度地表火、中度地表火和弱度地表火 3种类型 ,其区分指标分别为地表可燃物载量 1 4 0kg/m2 和地表可燃物绝对含水率 4 0 %。据此 ,秦岭林区潜在火行为共划分为 9种类型 ,分别为强度树冠火强度地表火类型 (D >0 37kg/m3,W≥ 1 4 0kg/m2 ,μ<4 0 % )、强度树冠火中度地表火类型 (D >0 37kg/m3,W≥ 1 4 0kg/m2 ,μ≥ 4 0 %或W <1 .4 0kg/m2 ,μ<4 0 % )、强度树冠火弱度地表火类型 (D >0 37kg/m3,W <1 4 0kg/m2 ,μ≥ 4 0 % )、弱度树冠火 ( 0 1 1kg/m3≤D≤ 0 37kg/m3)强度地表火类型、弱度树冠火中度地表火类型、弱度树冠火弱度地表火类型、无树冠火 (D <0 1 1kg/m3)强度地表火类型、无树冠火中度地表火类型和无树冠火弱度地表火类型 相似文献
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The basal area and height growth of trees and saplings in silver fir–European beech single stem selection forest were studied
with regard to their social status and crown parameters of size, coverage, shading and vitality. On 24 permanent research
plots (20 m × 20 m each) all trees [diameter at breast height (dbh) ≥10 cm] and saplings (≥1.3 m tall and dbh <10 cm) were
surveyed. Repeated measurements of dbh (N = 1,608) and height (N = 1,135) 10 years apart enabled the calculation of annual basal area increment (BAI) of trees and saplings, and annual height
(HI) increment of saplings. To obtain the growth characteristics for individual trees and saplings, their social status and
crown parameters were assessed by rank. In the multivariate general linear model for BAI, social status, crown size and crown
coverage of individuals as the predictors, and dbh2 as the covariate, explained 70% of total variability. Similarly, social status, crown size, crown coverage and crown shading
had a significant impact on the HI of saplings, explaining 70% of total variability. Among the observed variables, social
status determined according to the individual’s position in vertical stand structure was, in addition to dbh, the most important
predictor for both BAI and HI. Significant differences were observed between the BAI and HI models for the main tree species
(European beech and silver fir), indicating their different growth characteristics. The applied method could be used as a
supplement to the more widely used approaches for studying basal area and height growth of individual trees in selection forest
stands. 相似文献