In the conditions of Central Europe, silver birch (Betula pendula Roth) has so far not been an important species for commercial purposes but might be relevant from ecological point of view. For instance, prompt succession by birch and other pioneer tree species at large-scale post-disturbance areas is necessary to compensate for previous carbon losses by natural disasters. Therefore, our attention was focused on 14-year-old birch trees growing at the wind-thrown area in the High Tatra Mts. (northern Slovakia). We sampled aboveground biomass of 20 silver birch trees representing four classes of crown competition: 0 a?? competition free crowns, 1 a?? crowns under mild competition, 2 a?? crowns under moderate competition, 3 a?? crowns under severe competition. We studied biomass allocated to stems, branches and foliage, and basic properties of stems and foliage. The crown-competition free birches were nearly 13 m high, and their aboveground tree biomass was 150 kg. The biomass of birches under severe competition was five times lower. Crown competition modified biomass ratios of foliage to branch as well as of branch to stem. Our results showed that birches under severe competition stress invest more in height than in diameter. At the same time, crown competition modified foliage weight and specific leaf area (SLA), which was clear mostly in the upper part of the crowns. However, foliage area was influenced by crown competition only to a negligible extent. Our main finding is that foliage position (upper, middle or lower third of crown) affected foliage properties more than intraspecific crown competition. Finally, we pointed out that silver birch is a rather productive species that is not ecologically demanding. Therefore, it might be a prospective tree species under the ongoing climate change and the present period of intensification in renewable resources utilisation.
展开▼
机译：在中欧的条件下，银桦（Betula Pendula Roth）到目前为止还不是商业目的的重要物种，但可能与生态学的角度相关。例如，在大规模后扰动区域的桦树和其他先锋树种类的提示是弥补自然灾害以前的碳损失所必需的。因此，我们的注意力集中在14岁的桦树树上，在高Tatra MTS中生长在风抛。 （北斯洛伐克）。我们在20枚银桦树的地上进行采样，代表四级皇冠竞赛：0 a ??竞争免费冠，1 a ??温和的竞争下的冠，2个？冠冕在中等竞争下，3 A ??严重竞争下的冠冕。我们研究了分配给茎，分支和叶子的生物量，以及茎叶和叶子的基本性质。冠竞争自由桦树近13米，其地上的树木生物量为150公斤。严重竞争下的桦树生物质较低了五倍。 Crown竞赛改性叶子的生物质比例到分支以及分支到茎。我们的研究结果表明，严重竞争压力下的桦树高于直径的高度。同时，皇冠竞赛改性的叶子重量和特定叶面积（SLA），主要在冠上的上部清晰。然而，叶子区域受冠竞争的影响，只能忽略不计程度。我们的主要观点是树叶地位（皇冠的上部，中部或下三分之一）受到拆散冠竞赛的叶子属性。最后，我们指出，银桦是一种不太高效的物种，不太苛刻。因此，在持续的气候变化和可再生资源利用率的加强期间，它可能是一个未来的树种。
展开▼
