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首页> 外文期刊>Australian Forestry >Estimating the accuracy of tree ageing methods in mature Eucalyptus obliqua forest, Tasmania
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Estimating the accuracy of tree ageing methods in mature Eucalyptus obliqua forest, Tasmania

机译：塔斯马尼亚成熟桉树林中树木老化方法的准确性估算

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Estimates of tree age are important for making management decisions on the tree hollow resource because hollows suitable for fauna occur with greater frequency in older trees. The methods used to age trees vary with the practicalities of obtaining wood samples and the quality of the wood samples available. Ring counting is commonly used on smaller sample sizes when complete wood samples are available. When wood samples are incomplete, a combination of ring counting and extrapolation is often used. When no wood samples are obtained, growth models are generally used to estimate tree age. This paper uses all three methods, including three different growth models, to examine the accuracy of ageing trees. Simple regressions between tree age and diameterat breast height (over bark, dbh) provided the most accurate growth models at a site. Age estimates obtained from such models, however, had unacceptably large errors when few trees were used or when variable growth rates occurred. Under these circumstances, smaller errors margins were obtained from using a model based on tree dbh and site attributes than when averaging growth rates across sites. The estimated error in tree age estimates when using ring counting and extrapolation was about 10% of the tree age. The error of extrapolation increased with the amount of wood sample that was missing. Error margins were large for the oldest trees (average ±42.4 y for trees >350 y old) but less than ± 15 y for most (73%) of the trees estimated to be 100-300 yof age. These middle-aged trees are often the most useful to study when examining the rate of hollow production in eucalypts. Therefore, age estimates acquired in this way are generally accurate enough to be useful for making management decisions regarding the tree-hollow resource in production forests.
机译：树木年龄的估计对于制定树木空心资源的管理决策非常重要，因为适合动物区系的空心在老树中发生的频率更高。树木老化的方法随获取木材样品的实用性和可用木材样品的质量而异。如果有完整的木材样品，通常在较小的样品尺寸上使用环计数。当木材样品不完整时，通常会结合使用环计数和外推法。当没有木材样品时，通常使用生长模型来估计树木的年龄。本文使用所有三种方法（包括三种不同的生长模型）来检查衰老树的准确性。树木年龄与乳房高度（超过树皮，dbh）的直径之间的简单回归提供了一个站点上最准确的生长模型。但是，当使用很少的树木或发生可变的增长率时，从此类模型获得的年龄估计值会有不可接受的大误差。在这种情况下，与基于站点的平均增长率相比，使用基于树dbh和站点属性的模型获得的错误容限较小。使用环计数和外推法时，树木年龄估计的估计误差约为树木年龄的10％。外推误差随缺少的木材样品数量而增加。对于最老的树木，误差容限很大（对于> 350 y的树木，平均误差为±42.4 y），但是对于估计年龄为100-300 y的大多数树木，误差容限小于±15 y。在检查桉树中空果率时，这些中年树木通常是最有用的研究对象。因此，以这种方式获取的年龄估计值通常足够准确，可用于做出有关生产林中树洞资源的管理决策。

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