交趾黄檀1年生容器苗分级标准研究

【目的】开展1年生交趾黄檀Dalbergia cochinchinensis容器苗质量评价,为其壮苗培育和人工林规模发展提供技术支撑。【方法】应用主成分分析法确定交趾黄檀苗木分级指标,通过平均值±标准差法和逐步聚类法比较分析各等级苗木比例、标准以及在广东阳江、高明和福建漳州不同级别苗木的早期造林效果的差异,确定合理的交趾黄檀苗木质量分级方法与分级标准。【结果】苗高(H)和地径(D) 2个性状的主成分贡献率分别为59.85%和26.02%,累积方差贡献率为85.87%,H和D可作为1年生交趾黄檀苗木分级指标,各等级苗木之间存在着显著差异。2种不同方法确定的交趾黄檀各等级苗木比例、等级取值范围无明显差异。应用平均值±标准差法分级的交趾黄檀合格苗(Ⅰ和Ⅱ级苗)在各试验点的早期生长表现良好、造林成活率(90%以上)较高;造林3和12个月时,苗木建成形态和成活率与造林时的H和D呈极显著正相关。【结论】综合各等级苗木比率、等级取值范围、早期造林效果以及实际育苗生产过程,1年生交趾黄檀苗木质量分级宜采用平均值±标准差法,其分级标准为:Ⅰ级苗,H≥119.76 cm,D≥7.66 mm;Ⅱ级苗,69.62 cm≤H 119.76 cm,5.04 mm≤D 7.66 mm;Ⅲ级苗,H 69.62 cm,D 5.04 mm。     

The influence of timber harvest on the structure and composition of riparian forests in the Coastal Redwood region

The composition and structure of riparian forests in the coast redwood region were analyzed in relation to the length of time since timber harvest, and the width of riparian buffer zone. Ten sites were sampled in the central range of the coast redwood forest type within a variety of post-harvest age groups and riparian buffer zone widths. Data was collected using randomly selected sample plots adjacent to perennial coastal steams. Correlation Fisher's r to z tests and two-tailed t-test were used to examine the relationship between the sample variables and the experimental parameters “years since harvest”, and “width of buffer.” Results indicate that canopy cover was negatively correlated to “years since harvest” with the highest level of canopy cover found on the youngest sites and the lowest level found on the old-growth sites. The hardwood to conifer dominance ratio and the basal area of Alnus rubra (red alder) were correlated negatively to both “years since harvest” and “buffer width” indicating that timber harvest favored hardwood species. Late seral associates such as Oxalis oregana (redwood sorrel), Anthyrium filix-femina (lady fern), and Vaccinium parviflorum (billberry) were found preferentially in older forests and sites with wider buffer zones, while non-native species such as Hedera helix (English ivy), Pampas cortedaria (pampas grass), and Myosotis latifolia (forget-me-not) were found preferentially in younger forests and areas with smaller buffer zones.     

The effects of timber harvesting on the structure and composition of adjacent old-growth coast redwood forest,California, USA

Data collected across timber harvest boundaries on nine sites within the Redwood National and State Park management area in California, USA, were used to estimate the effective size of old-growth coast redwood preserves. Fourteen variables related to stand structure and composition, wildlife habitat, and physical environment were significantly correlated to distance from the timber harvest boundary using multiple regression analysis. A maximum depth of edge influence of 200 m was determined for variables exhibiting a significant correlation to the distance from the harvest edge. A spatial analysis using ArcView indicated that 53% of the old growth preserved within the study area was influenced by edge conditions, leaving 47% as effective old-growth.This revised version was published online in May 2005 with corrections to the Cover Date.     

沿海地区水杉林带生物产量的时空结构特征

根据江苏沿海地区水杉林带中３３ 株标准木生物量的测定资料,分析了不同立地类型、不同林龄阶段水杉林带生物产量的结构特征。结果表明：旱作田水杉林带总生物产量稍高于水旱轮作田,但旱作田水杉林带的干量相对分配率小于水旱轮作田,而根量、枝量和叶量的相对分配率则大于水旱轮作田;随着林龄的增长,两立地类型水杉林带的干量相对分配率相应增大,根量、枝量和叶量的相对分配率相应减少;旱作田水杉林带生物生产力高于水旱轮作田,旱作田年平均净生产量由６ ａ 生的３－３６１ ｔ／（ｈｍ２·ａ） 增至１９ ａ 生的１７－５９２ ｔ／（ｈｍ２·ａ） ,水旱轮作田则由５ ａ 生的２－４９１ ｔ／（ｈｍ２·ａ） 增至１５ ａ 生的１０－６２２ｔ／（ｈｍ２·ａ） 。     

对红木家具与“红木”生产现状与发展的探讨

对红木家具与红木树种用材标准、产品标准,着重就红木标准、产品标准、红木家具选购、真假红木以及红木树种扩大或延伸等行业性问题进行了分析和探讨,提出了《红木》标准部分内容修订、适度增加红木树种等建议。     

Structure, allometry, and biomass of plantation Metasequoia glyptostroboides in Japan

We quantified structural features and the aboveground biomass of the deciduous conifer, Metasequoia glyptostroboides (Hu and Cheng) in six plantations in central Japan. In order to derive biomass estimates we dissected 14 M. glyptostroboides trees into three structural components (stem wood, branch wood and foliage) to develop allometric equations relating the mass of these components and of the whole tree to diameter at breast height (DBH). We found robust relationships at the branch and whole tree level that allow accurate prediction of component and whole tree biomass. Dominant tree height was similar within five older (>40 years) plantations (27–33 m) and shorter in a 20-year-old plantation (18 m). Average stem diameter varied from 12.8 cm in the youngest stand to greater than 35 cm in the oldest stand.

Metasequoia have relatively compact crowns distributed over the top 30% of the tree although the youngest stand had the deepest crown relative to tree height (up to 38%). At the individual tree level in older stands, 87% of the aboveground biomass was allocated to the stem, 9% to branch wood and 4% to foliage. We found little difference in the relative distribution of above ground biomass among the stands with the exception of lower foliage biomass in larger diameter trees. Total aboveground biomass of the older stands varied twofold, ranging from a maximum of 450 Mg ha⁻¹ in a 42-year-old stand to a minimum of 196 Mg ha⁻¹ in a 48-year-old stand. Total above ground biomass of the 20-year-old stand was 176 Mg ha⁻¹.