Factors affecting snow damage of trees with particular reference to European conditions.
Factors affecting snow damage of trees with particular reference to European conditions.
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DOI：
10.14214/sf.a8519
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发表时间：
1997
期刊：
影响因子：
1.8
通讯作者：
M. Nykänen;H. Peltola;C. Quine;S. Kellomäki;M. Broadgate
中科院分区：
文献类型：
--
作者：
M. Nykänen;H. Peltola;C. Quine;S. Kellomäki;M. Broadgate
在欧洲共同体内，雪灾每年影响约400万米的木材，给森林所有者造成重大经济损失。例如，在北欧，雪灾的发生在过去几十年里有所增加，这主要是由于总蓄积量的增加。最常见的损害形式是树干折断，但树木也可能被弯曲或连根拔起。遭受雪害的树木也更容易因昆虫或真菌的攻击而受到损害。树上的积雪很大程度上取决于天气和气候条件。温度会影响雪的水分含量，从而影响雪在树枝上堆积的程度。风可能会导致降雪，但也可能导致大量湿雪、雾霾或冻雨。潮湿的雪最有可能出现在秋末或初春。地理位置和地形影响雪害形态的发生，沿海地区和中高海拔地区积雪较多。坡度起次要作用，坡向作用的证据是矛盾的。破坏性事件的发生可能从每年冬天到每10年左右一次不等，具体取决于区域气候。未来，假设北纬地区全球变暖，降雪破坏的风险可能会增加，因为零度附近降雪的相对发生率可能会增加。雪害的严重程度与树木特性有关。树干锥度和树冠特征是控制树木稳定性的最重要因素。茎稍变细、树冠不对称和僵硬的水平分支都与高风险相关。然而，由于与地理位置的相互作用，关于物种差异的证据不太清楚。森林管理可以通过选择更新、抚育、间伐和轮伐来改变风险。然而，目前还不可能量化和比较这些措施的绝对效果。需要一个综合的风险模型，以评估各种地点和营林栽培因素。提出了构建这样一个模型的计划，并强调了知识方面的差距。
Within the European Community snow damage affects an estimated 4 million m of timber every year, causing significant economic losses to forest owners. In Northern Europe, for example, the occurrence of snow damage has increased over the last few decades mainly due to the increase in total growing stock. The most common form of damage is stem breakage, but trees can also be bent or uprooted. Trees suffering snow damage are also more prone to consequential damage through insect or fungal attacks. Snow accumulation on trees is strongly dependent upon weather and climatological conditions. Temperature influences the moisture content of snow and therefore the degree to which it can accumulate on branches. Wind can cause snow to be shed, but can also lead to large accumulations of wet snow, rime or freezing rain. Wet snow is most likely in late autumn or early spring. Geographic location and topography influence the occurrence of damaging forms of snow, and coastal locations and moderate to high elevations experience large accumulations. Slope plays a less important role and the evidence on the role of aspect is contradictory. The occurrence of damaging events can vary from every winter to once every 10 years or so depending upon regional climatology. In the future, assuming global warming in northern latitudes, the risk of snow damage could increase, because the relative occurrence of snowfall near temperatures of zero could increase. The severity of snow damage is related to tree characteristics. Stem taper and crown characteristics are the most important factors controlling the stability of trees. Slightly tapering stems, asymmetric crowns, and rigid horizontal branching are all associated with high risk. However, the evidence on species differences is less clear due to the interaction with location. Management of forests can alter risk through choice of regeneration, tending, thinning and rotation. However, quantification and comparison of the absolute effect of these measures is not yet possible. An integrated risk model is required to allow the various locational and silvicultural factors to be assessed. Plans are presented to construct such a model, and gaps in knowledge are highlighted.