Tingey David T, Phillips Donald L, Johnson Mark G
U.S. Environmental Protection Agency, Western Ecology Division, Corvallis, OR 97333, USA.
New Phytol. 2003 Jan;157(1):155-161. doi: 10.1046/j.1469-8137.2003.00653.x.
• When using minirhizotrons to study fine dynamics in natural ecosystems, it is important to determine how sample collection frequency influences estimates of fine root production and mortality. Minirhizotron images were collected twice per week from mature Pseudotsuga menziesii and Tilia cordata trees and analyzed to estimate fine root production and mortality. These data were used to create data sets reflecting sample frequencies of 1, 2, 4 or 8 wk. • When the sampling interval is long, fine roots can appear and disappear between samplings, leading to underestimates of production and mortality. For example, with an 8-wk sample frequency, 24 and 35% of the fine root production in P. menziesii and T. cordata , respectively, is not measured. Fine root mortality displays the same sensitivity to sample frequency. • Our experimental observations supported the previously published simulation analysis, which provides an estimate of the proportion of fine roots missed at different sample frequencies and is a tool that can be used to select a sample frequency to balance production and mortality accuracy with sampling and analytical effort.
• 使用微根管研究自然生态系统中的细根动态时，确定样本采集频率如何影响细根生产和死亡率的估计非常重要。每周从成熟的花旗松和心叶椴树上采集两次微根管图像，并进行分析以估计细根生产和死亡率。这些数据用于创建反映1、2、4或8周样本频率的数据集。
• 当采样间隔较长时，细根可能在采样之间出现和消失，导致对生产和死亡率的低估。例如，在8周的样本频率下，花旗松和心叶椴树中分别有24%和35%的细根生产未被测量。细根死亡率对样本频率表现出相同的敏感性。
• 我们的实验观察结果支持了先前发表的模拟分析，该分析提供了在不同样本频率下错过的细根比例的估计，并且是一种可用于选择样本频率以平衡生产和死亡率准确性与采样和分析工作量的工具。
