Oren R, Werk K S, Schulze E-D, Meyer J, Schneider B U, Schramel P
School of Forestry and Environmental Studies, Duke University, 27706, Durham, NC, USA.
Lehrstuhl Pflanzenökologie der Universität Bayreuth, Postfach 101251, 8580, Bayreuth, Federal Republic of Germany.
Oecologia. 1988 Nov;77(2):151-162. doi: 10.1007/BF00379181.
A declining Picea abies (L.) Karst. stand produced as much foliage and branches as a healthy stand but less stemwood at a similar leaf area index and climate. Nutrient analyses revealed that most biomass components at the declining site had lower concentrations of calcium and magnesium, but similar nitrogen and potassium (except for lower potassium in younger needles) and higher phosphorus, manganese and aluminum than the respective components at the healthy site. Comparison of these data with the results from studies on the nutrition and growth of P. abies seedlings (Ingestad 1959) led to the conclusion that the healthy stand is in a balanced nutritional state, while trees at the declining stand have only 56% of the foliar magnesium concentration required to permit growth at a rate which could be achieved at their nitrogen status. It appears that acidic deposition, which involves an input of nitrogen and a leaching of cations from the soil, causes an imbalance in the availability of nitrogen and magnesium. Growth is eventually reduced as magnesium becomes limiting.
在相似的叶面积指数和气候条件下，一片逐渐衰败的欧洲云杉林所产生的树叶和树枝量与一片健康林相同，但茎干木材量较少。养分分析表明，衰败林地的大多数生物量组成部分的钙和镁浓度较低，但氮和钾含量相似（除了较嫩针叶中的钾含量较低），且磷、锰和铝含量高于健康林地的相应组成部分。将这些数据与欧洲云杉幼苗营养与生长研究结果（英格斯塔德，1959年）进行比较后得出结论，健康林处于营养平衡状态，而衰败林中的树木叶片镁浓度仅为以其氮素状况所能达到的生长速率所需浓度的56%。似乎涉及氮输入和土壤阳离子淋失的酸性沉降导致了氮和镁有效性的失衡。随着镁成为限制因素，生长最终会减缓。
