菌根化技术在广西马尾松育苗中的应用

通过对马尾松苗木的菌根土接种及苗圃地选择的试验,可知培育马尾松菌根化苗木,应选择土壤中菌根菌含量丰富的马尾松疏残林地、近年采伐迹地、林中空地、林缘下方,以及前茬是马尾松或湿地松的老苗圃地作为马尾松苗圃地。在这些地类上,结合施以足量腐熟有机肥做基肥,培育的马尾松苗木菌根感染率一般都在85%以上,苗木质量好。上述地类外的新垦苗圃地,应在生长健壮,无病原菌,而且最好是生长有马勃子实体的马尾松林下,挖取0—20厘米表土层进行菌根土接种,培育的松苗也可获得较高的菌根感染率。历史上未种过松类、栎类,附近又无松林的荒山荒地,用作马尾松苗圃地,苗木的菌根感染率极低,质量差。     

不同烈度林火对油松林潜在地表火行为的影响

油松是我国华北地区代表性树种之一,含有丰富油脂,容易引发大面积高烈度森林火灾。阐明不同烈度林火对油松林地表可燃物负荷量和潜在地表火行为的影响,对于油松林林火管理具有重要意义。以辽河源自然保护区2014年不同烈度林火干扰后油松林分为研究对象,根据不同烈度(重度、中度、轻度)和对照(未过火)分别设置3块20 m×20 m样地,共12块样地,调查地表可燃物和林分结构指标,结合室内实验,利用BehavePlus 5.0软件进行潜在火行为模拟,探讨不同烈度林火5年后油松林地表可燃物负荷量和潜在地表火行为特点,并分析影响潜在地表火行为的主要因素。研究结果表明：(1)不同烈度林火之间,细小可燃物负荷量和地表可燃物总负荷量均不存在显著性差异(P>0.05)。(2)不同烈度林火后,在不同风速和可燃物含水率条件下,油松林潜在地表火蔓延速度、火线强度不存在显著性差异(P>0.05),单位面积发热量、火焰高度、反应强度存在显著性差异(P<0.05)。(3)不同烈度林火后油松林潜在地表火行为主要受油松更新幼苗基径、灌木负荷量、油松平均冠幅、上层枯叶负荷量、油松更新幼苗密度的影响。研究结果表明不...     

亚热带人工林松树~(13)C/~(12)C比率和水分利用效率

1 引言 亚热带季风阔叶林自然林被破坏后,代之以人工林,由于自然林郁密的树冠层的消失,引起环境因素明显变化,如太阳辐射的增强,气温变幅变大,同时由于风速增大,加大了蒸腾的需要量,造成空气相对湿度降低和土壤水分亏缺,特别是在干旱季节尤为显著。该林地中除被动适应这一生境的1年生草本外,尚有灌木桃金娘(Rhodomyrtus tomentosa)、三叉苦(Euodia     

分布区西缘油松种群的生长特征

 在青海省互助北山林场和贵德东山林场的油松林内分别设置6个和5个样方,对分布区西缘的天然油松种群的生长特征进行了生态学研究。结果表明,两地的油松种群均为复层异龄结构;树高与胸径的关系揭示东山的油松种群其生长能力仅为北山的一半;种群内个体的树高直径比与个体的大小呈负相关,表明个体生长对被压的生态适应;两地个体的直径生长过程也差异很大,即东山油松的直径生长随年龄的增长呈下降趋势,而北山呈上升趋势或变化很小。上述差异导致两地的生产力差异很大：北山可望获得200t／ha的生物量,而东山仅约为100t/ha,但两地的生物量密度差异不大,为7一11t／ha．m,利用生物量密度与总胸高断面积之间的线性关系,可以建立良好的推算种群地上部生物量的方法。本文还对天然油松的种群密度与平均个体重之间的关系作了讨论。     

广东乳阳山地广东松、长苞铁杉原生林的结构特征和动态分析

对乳阳林区亚热带山地广东松(Pinus kwangtungensis)、长苞铁杉(Tsuga longibracteata)原生林及其与阔叶树的混交林结构特征和动态作了论述和分析,并从森林群落演替的观点出发提出了保护和利用的建议。     

Quantifying carbon storage and sequestration by native and non-native forests under contrasting climate types

Non-native trees may have significant impacts on the carbon sink capacity of forested lands. However, large-scale patterns of the relative capacity of native and non-native forests to uptake and store carbon remain poorly described in the literature, and this information is urgently needed to support management decisions. In this study, we analyzed 17,065 plots from the Spanish Forest Inventory (covering c. 30 years) to quantify carbon storage and sequestration of natural forests and plantations of native and non-native trees under contrasting climate types, while controlling for the effects of environmental factors (forest structure, climate, soil, topography, and management). We found that forest origin (non-native vs. native) highly influenced carbon storage and sequestration, but such effect was dependent on climate. Carbon storage was greater in non-native than in native forests in both wet and dry climates. Non-native forests also had greater carbon sequestration than native ones in the wet climate, due to higher carbon gains by tree growth. However, in the dry climate, native forests had greater carbon gains by tree ingrowth and lower carbon loss by tree mortality than non-native ones. Furthermore, forest type (classified by the dominant species) and natural forests versus tree plantations were important determinants of carbon storage and sequestration. Native and non-native Pinus spp. forests had low carbon storage, whereas non-native Eucalyptus spp. forests and native Quercus spp., Fagus sylvatica, and Eurosiberian mixed forests (especially not planted ones) had high carbon storage. Carbon sequestration was greatest in Eucalyptus globulus, Quercus ilex, and Pinus pinaster forests. Overall, our findings suggest that the relative capacity of native and non-native forests to uptake and store carbon depends on climate, and that the superiority of non-native forests over native ones in terms of carbon sequestration declines as the abiotic filters become stronger (i.e., lower water availability and higher climate seasonality).     

Bud break and multiple shoot formation from tissues of mature trees ofPinus caribaea andPinus kesiya

Summary Proliferation of terminal and axillary buds of 20 yr-oldPinus caribaea andP. kesiya trees was obtained on half strength DCR medium supplemented with 0.5 mg&#x00B7;liter^&#x2212;1 6-benzylaminopurine (BA). These sprouts further elongated with the formation of multiple shoots with the ratio of 1:3, on transfer to medium in which the 0.25 mg&#x00B7;liter^&#x2212;1 BA of the initiation medium was replaced by 0.25 mg&#x00B7;liter^&#x2212;1 kinetin. Rooting was obtained on the same medium. Plantlets thus formed were transferred to perlite:peat:vermiculite mixture (1:1:1) in polybags (10&#x00D7;5 cm) under 80&#x00B1;5% humidity in a polyhouse. Plantlets ofP. caribaea andP. kesiya were established with 72.5 and 83.3% survival, respectively.     

马尾松正常木与应压木的比较解剖

用光学显微镜和扫描电镜观察比较了马尾松(Pinus massoniana)正常木与应压木的结构差异。研究结果表明:马尾松应压木从早材到晚材呈缓变,管胞在横切面上除生长轮分界处的两侧外均为圆形,管胞之间具明显的胞间隙;管胞的次生壁仅有 S_1和 S_2两层;次生壁上螺纹间隙和螺纹裂隙都很明显,并与 S_2层微纤丝平行。此外,还初步讨论了应压木形成的可能机理。     

Jack pine of all trades: Deciphering intraspecific variability of a key adaptive trait at the rear edge of a widespread fire-embracing North American conifer

Premise

Understanding mechanisms fostering long-term persistence of marginal populations should provide key insights about species resilience facing climate change. Cone serotiny is a key adaptive trait in Pinus banksiana (jack pine), which shows phenotypic variation according to the fire regime. Compared to range-core populations within the fire-prone boreal forest, low and variable serotiny in rear-edge populations suggest local adaptation to uncommon and unpredictable wildfire regime. We assessed environmental/physiological factors that might modulate intraspecific variation in cone serotiny.

Methods

We experimentally subjected closed cones to incrementing temperatures, then tested seed germination to determine whether and how various ecological factors (cone age, branch height, tree size, tree age) are related to cone dehiscence and seed viability in jack pines from rear-edge and range-core populations in eastern Canada.

Results

Cones from rear-edge populations dehisce at a lower opening temperature, which increases with cone age. Cones from range-core stands open at a more constant, yet higher temperature. Cones from rear-edge stands take between 13 and 27 years to reach the level of serotiny achieved at the range core. At the rear edge, seed viability is steady (51%), whereas it decreases from 70% to 30% in 20 years at the range core.

Conclusions

We inferred the mechanisms of a bet-hedging strategy in rear-edge populations, which ensures steady recruitment during fire-free intervals and successful postfire regeneration. This capacity to cope with infrequent and unpredictable fire regime should increase the resilience of jack pine populations as global changes alter fire dynamics of the boreal forest.     

Photosynthetic acclimation to elevated atmospheric carbon dioxide and UV irradiation in Pinus banksiana

Pinus banksiana seedlings were grown for 9 months in enclosures in greenhouses at CO₂ concentrations of 350 or 750 μmol mol⁻¹ with either low (0.005 to 0. 3 W m⁻²) or high (0.25 to 0. 90 W m⁻²) ultraviolet-B (UV-B) irradiances. Total seedling dry weight decreased with high UV treatment but was unaffected by CO₂ enrichment. High UV treatment also shifted biomass partitioning in favor of leaf production. Both CO₂ and UV treatments decreased the dark respiration rate and light compensation point. High UV light inhibited photosynthesis at 350 but not at 750 μmol mol⁻¹ CO₂ due to a UV induced increase in ribulose-1, 5-bisphosphate carboxylase/oxygenase efficiency and ribulose-1, 5-bisphosphate regeneration. Stomatal density was increased by high UV irradiance but was unchanged by CO₂ enrichment.