Reconstructing past structure and nitrogen accumulation of free populations, and test of its accuracy

我们通过将该技术应用于26年生的杉木人工林，并将估计的森林结构与观察到的森林结构进行比较，测试了根据现有样本重建树木种群结构和功能的方法的准确性。取样于2000年10月，在一日高冈世博会的一块施肥试验田进行。札幌的森林。测定了对照小区和年度施肥小区的胸径、树高、冠长等指标。然后砍伐10棵树，测量它们的植物部分生物量。茎圆盘被用来估算边材面积。还收集了圆盘用于茎分析，以估计茎体积和生长。2001年10月进行了额外的抽样。然后，对所有样本进行分析，以建立树木大小与植株部位、生长等之间的异速生长关系。还收集树木样本进行氮浓度分析：将其干燥、研磨，然后用N-C分析仪进行氮浓度分析。研究林分中存在单株胸径的时间序列数据。利用树木异速生长的附加信息，估算了林分总生物量、植物部分生物量、叶面积及其生长量等。对于没有样地数据的年份，我们采用Osawa等人的林分重建方法。(2000)，并估算了林分总结构和含氮量。还分析了树干氮素浓度与边材体积、边材体积与树大小以及树干大小分布之间的关系。我们发表了两篇关于林分重建理论中估计精度的原创论文。

We tested accuracy of the method for structural and functional reconstruction of tree populations from the existing samples, by applying this technique to a 26-year-old plantation of Todo-fir, and comparing the estimated and observed structures of the forests. Sampling was done in Oct. 2000, at a fertilization experiment plots in Hitsujigaoka Exp. Forest in Sapporo. Tree dbh, height and crown length etc. were measured in both control and annually fertilized plots. Then ten trees were felled, and their plant-part biomass values were measured. Stem discs were taken for estimation of sapwood areas. Discs were also collected for stem analysis for estimation of stem volume and growth. Additional sampling was done in Oct. 2001. Then, all samples were analyzed together to develop allometric relationships between tree size and plant part, growth, etc. Tree samples were also collected for analysis of nitrogen concentration: they were dried, ground, then analyzed with the N-C analyzer for N concentration. Time series data of dbh exists for individual trees in the studied stands. With the additional information of tree allometry, we estimated for the total stands, plant-part biomass, leaf area, their growth etc. For the years without plot data, we applied the stand reconstruction method of Osawa et al. (2000), and total stand structure and nitrogen content were estimated. Also analyzed for this calculation were relationships between stem nitrogen concentration vs. sapwood volume, sapwood volume vs. tree size, and stem size distribution. We published two original papers on accuracy of estimates in the theory of stand reconstruction.