金沟岭云冷杉针阔混交林林分结构研究

以吉林汪清金沟岭林场1 hm2云冷杉针阔混交林数据为研究基础,对样地内树种组成、直径结构以及树种的空间分布结构进行分析。结果表明:1)优势物种云杉Abies nephrole-pis、冷杉Picea koraiensis、枫桦Betula costata大径阶的单木占多数,云冷杉的峰度值小于0,直径分布较为分散,枫桦峰度值大于0,直径分布比较集中。在物种的胸径分布格局解释上,负指数模型的解释程度要优于Weibull模型。2)该群落树种的平均角尺度为0.545,空间分布格局呈聚集分布,3种优势树种的平均角尺度为0.475～0.517,呈现随机分布特征。3)云杉、枫桦的平均混交度较高,而冷杉的平均混交度相对较低。4)样地所有物种的平均大小比数为0.496,3种主要树种的平均大小比数排序为云杉<冷杉<枫桦,表明云杉竞争力最大,冷杉次之,而枫桦的竞争力最小。该林分结构较为复杂,群落内树种以聚集分布为主,所以应调整林分林木分布格局,促进林木向随机分布格局发展,同时伐除上层的"霸王树"以及病腐木、弯曲树等处于竞争劣势的林木,将混交度维持在中度混交,从而尽可能保留维持群落的物种多样性。     

亚高山暗针叶林凋落物的分解过程

凋落物是森林生态系统的重要组成部分,其分解过程是森林生态系统养分循环的重要环节。准确测定凋落物的分解动态,对研究森林生态系统的格局和过程非常重要。本文的工作在贡嘎山高山生态系统观测试验站开展,对海拔3 000 m的峨眉冷杉(Abies fabri)林进行定位观测,并对峨眉冷杉林凋落物分解过程进行了长期测定。研究结果表明:(1)凋落物的分解速率是阔叶>针叶>枯枝,峨眉冷杉林的阔叶、针叶和枯枝等凋落物分解一半所需要的时间分别为6.8年、10.5年和14.5年,分解95%所需时间分别为29.3年、45.6年和63.1年;(2)无论阔叶还是针叶、枯枝,其有机碳含量均随着时间的推移而下降,而有机碳分解率均随着时间而增高;利用指数衰减模型,获得凋落物有机碳的分解系数是阔叶>针叶>枯枝;(3)在每年凋落物输入峨眉冷杉林林地时,其中的阔叶、针叶和枯枝已经开始分解,当年可释放的有机碳分别为52.18 kg·hm^-2、4.32 kg·hm^-2和0.67 kg·hm^-2,各类凋落物每年有机碳释放总量为61.13 kg·hm^-2,占凋落时有机碳量的6.58%。     

色季拉山急尖长苞冷杉林下灌木群落空间格局及其与倒木关联性分析

分析西藏色季拉山急尖长苞冷杉原始林下灌木群落的空间分布格局及其与倒木的关联性，探讨该森林生态系统内灌木的分布规律，并从空间分布格局角度量化倒木对灌木分布的影响。以色季拉山急尖长苞冷杉原始林下灌木和倒木为研究对象，通过典型样地调查，用点格局法分析其空间分布格局以及与倒木的关联性。结果表明:1）样地内共有灌木7种，总密度730株·hm^-2，不同灌木种群分密度依次为杯萼忍冬（359株·hm^-2）>长尾槭（185株·hm^-2）>西南花楸（61株·hm^-2）>猴斑杜鹃（55株·hm^-2）>冰川茶藨子（53株·hm^-2）>光秃绣线菊（株·hm^-2）>峨眉蔷薇（株·hm^-2）；2）在0~50 m空间尺度内，冰川茶藨子、猴斑杜鹃、长尾槭、杯萼忍冬以集群分布为主要特征；西南花楸以随机分布为主要特征，只是在个别尺度呈现显著的集群分布；3）Ⅰ腐烂等级倒木与灌木在0~50 m空间尺度上呈显著的负关联，倒木整体与灌木及Ⅱ~Ⅴ腐烂等级倒木与灌木在0~50 m空间尺度上均无显著关联。不同灌木种群因对环境的适应性不同而具有不同的空间分布格局，灌木空间格局形成的生态过程及倒木对灌木空间分布的影响均具有复杂性。     

Ecological environment analysis ofAbies holophylla plantations under different cutting systems

Different types of plantations were observed in Baishilazi National Nature Reserve, Liaoning Province, for 34 a. The environmental quality ofAbies holophylla plantations was analyzed under different cutting systems. Analysis factors included soil erosion rate, humification degree of litters, and water hold capacity. The surface soil loss of clear cutting area was 19000t·km⁻²·a⁻¹ more than that of selective cutting area. The content of soil organic matter in board-leaved—Abies holophylla forest was 4.62% more than that in pure stand, and the water hold capacity of the mixed forest was 1.43 time of that of pure stand. The mixed forest of board-leaved—Abies holophylla by selective cutting can upgrade the ecological environment quality. This paper is a part of a key project from Liaoning Science Committee. Responsible editor: Zhu Hong     

Stability of subalpine forest-meadow boundary inferred from size and age structure ofAbies mariesii thickets on a Japanese snowy mountain

Subalpine forest zone in the Japanese snowy mountains is characterized by a mosaic of coniferous forests and meadows.Abies mariesii thickets surround mesic meadows, forming a forest-meadow ecotone. Size and age structure of the thickets were studied to examine the stability of the forest-meadow boundaries on Mount Aizukomagatake in central Japan. The age structure indicates that the small height ofA. mariesii in the thickets was not due to the early stage of succession but due to adverse site conditions. In spite of their small stem height, they were as old as canopy trees in neighboringA. mariesii forests. Snow settling pressure madeA. mariesii thickets with broken main stems on the crest slopes, while snow glide pressure formed those with bending stems on leeward slopes. No evidence was found to show any major changes in the position of the forest-meadow boundaries in the size and age structure. The boundary position appears to have been almost steady for at least this century.     

蔗糖不同质量分数对杉松新鲜花粉萌发的影响

以杉松新鲜花粉为材料,测定在含有不同质量分数蔗糖固体培养基上萌发率,结果表明:花粉培养24 h之内形态基本无变化,培养至48 h时有花粉开始启动萌发,48 h后,花粉大量萌发,适宜培养时间为72 h。在蔗糖质量分数为5%培养基上花粉萌发率高于其他质量分数,萌发率均值为90.9%,最高值为95.1%。当质量分数为20%时,萌发率均值仅为51.4%。高质量分数蔗糖会抑制花粉萌发及花粉管伸长。     

Broadleaf competition interferes with balsam fir regeneration following experimental removal of moose

Changes to ecosystems caused by introduced herbivores can be predictable, stepwise transitions or unpredictable and even irreversible state changes. This study's objectives were to explore effects on forest succession and soil development 5 years after moose (Alces alces L.) were fenced out of areas within and adjacent to a national park in Newfoundland, Canada. Study plots spanned a range of understorey broadleaf plant associations with regenerating balsam fir (Abies balsamea (L.) Mill.), an important winter forage plant for moose and a dominant canopy tree throughout Newfoundland. After 5 years, height–diameter ratios were significantly larger for larger basal diameters of understorey balsam fir in unfenced, but not in fenced subplots, suggesting that growth of the conifer is compromised within the exclosure. In contrast, for most broadleaf trees and shrubs, moose removal by fencing results in greater heights and basal diameters than in control subplots. The competitive advantage of broadleaf trees and shrubs over balsam fir in the short-term may be a result of past sustained heavy moose browsing benefiting plants that are better at investing resources into below-ground growth or benefiting plants that have broader leaf canopies. It is not clear how long the broadleaf transition state we document will continue. Restorative actions intended to mimic usual patterns of forest regeneration in this region of Newfoundland might best consider moose removal with site preparation and/or planting to historic densities.     

贡嘎山冷杉林土壤CO_2释放的模拟研究

利用贡嘎山冷杉林1998年和1999年土壤CO_2通量对生物地球化学循环模型Forest-DNDC进行校准和验证,通过调整温度和湿度对土壤根呼吸影响的计算公式和对模型参数的本土化,提高了模拟值与真实值之间的吻合程度,尤其是提高了冬季土壤CO_2释放模拟的准确性.校准后使土壤CO_2日释放量模拟结果的平均误差((-e))和相对平均误差((-e)')分别下降了3.81 kg/hm~2和13.49%,绝对平均误差(M)和相对绝对平均误差(M')也同时降低;模型效率的Nash-Sutcliffe系数(Me)和冷模拟(利用默认参数)相比,也由0.651提高到0.683.模型验证结果表明,冷杉林土壤CO_2释放通量模拟值大体上能够与实际观测值的季节变化和日变化保持一致,在释放的量上也与实际观测值相当.     

Effect of simulated acid fog on membrane-bound calcium (mCa) in fir (Abies firma) and cedar (Cryptomeria japonica) mesophyll cells

The decline of virgin fir (Abies firma) forest at Mt. Oyama has been reported. Related field observations suggest that high acidity fog is linked with its decline. However, cedar (Cryptomeria japonica) in the same area shows no symptoms of decline. For assessing effects of acid fog on membrane-bound calcium (mCa) of the leaf mesophyll cells, 9-year-old seedlings of fir (Abies firma) and 8-year-old seedlings of cedar (Cryptomeria japonica) were exposed twice a week to simulated acid fog (SAF at pH 3 with pH 5 as control) for 2 h per day in a chamber during May–December 2007 (except August). Current and 1-year-old needles were collected from seedlings and analyzed at 1-month intervals. For current-year needles of fir, mCa levels in cells exposed to SAF at pH 3 were significantly lower than in cells exposed to pH 5, especially during September 2007–March 2008. In contrast, it is noteworthy that mCa levels of cedar were maintained as virtually constant irrespective of SAF acidity, indicating that fir is more sensitive to acid fog than is cedar. Based on these results, mCa loss by acid fog might also be caused in the declining virgin fir forest at Mt. Oyama.     

冷杉属植物遗传多样性研究进展及面临的问题

介绍了国内冷杉属植物的地理分布,同时对国内外冷杉属植物遗传多样性的研究进展进行了分析,总结了国内外对冷杉属植物遗传多样性不同水平的研究情况,提出了冷杉属植物遗传多样性研究中存在的问题,并提出了今后的研究方向。