Abstract Trunk inner rot is a common phenomenon in some old-growth pine dominated forests, making it impossible to determine tree age by counting annual rings. We compared the efficiency of five methods to estimate the age of hollow pine trees (Pinus sylvestris L.). Our main aims were to select the best-performing method and to test whether the age of the tree or the proportion of rot influences the accuracy of estimation. We used full increment cores (reaching the pith or within 1 cm of it) from 100 trees (54 to 562 years old) collected in northern Sweden and simulated rotten centres of three different sizes in order to test the methods. The lowest error rates were obtained when less than a third of the sample was missing (down to 5.0% error rate), and by using a method based on the growth pattern of a set of healthy trees. Using linear extrapolation of the mean radial growth led to large overestimates (up to three times the number of absent rings) with error rates up to 27.3%. We also found that the performance of all methods was reduced in cores from older trees. Our main conclusion is that non-linear methods should be preferred for age estimation of hollow pines. We also argue that more precision in the age estimation could be gained already in the field by collecting multiple cores from rotten trees or by developing alternative coring methods.

中文翻译：

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从茎腐病的增量核心估计老苏格兰松树年龄的新见解

摘要 树干内腐病是一些古老的松树为主的森林的普遍现象，无法通过计算年轮来确定树龄。我们比较了估计空心松树 (Pinus sylvestris L.) 年龄的五种方法的效率。我们的主要目标是选择性能最好的方法，并测试树的年龄或腐烂的比例是否会影响估计的准确性。我们使用了从瑞典北部收集的 100 棵树（54 至 562 岁）的完整增量核心（到达髓部或在其 1 厘米内），并模拟了三种不同大小的腐烂中心，以测试这些方法。当缺失少于三分之一的样本时（错误率降至 5.0%），并且使用基于一组健康树木的生长模式的方法，获得了最低的错误率。使用平均径向增长的线性外推导致高估（高达缺失环数量的三倍），错误率高达 27.3%。我们还发现所有方法的性能在来自旧树的核心中都有所降低。我们的主要结论是非线性方法应该优先用于空心松的年龄估计。我们还认为，通过从腐烂的树木中收集多个核心或开发替代的取芯方法，可以在现场获得更精确的年龄估计。