A novel approach in model-based mapping of soil water conditions at forest sites
A novel approach in model-based mapping of soil water conditions at forest sites
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DOI：
10.1016/j.foreco.2009.03.033
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发表时间：
2009-10
影响因子：
3.7
通讯作者：
K. Schwärzel;K. Feger;J. Häntzschel;Alexander Menzer;U. Spank;Falko Clausnitzer;B. Köstner;C. Bernhofer
中科院分区：
文献类型：
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作者：
K. Schwärzel;K. Feger;J. Häntzschel;Alexander Menzer;U. Spank;Falko Clausnitzer;B. Köstner;C. Bernhofer
了解特定地点的水条件对于林地评估非常重要，也是可持续森林管理的基础。在中欧，传统的场地测绘遵循综合生态方法。土壤水可用性的评估基于叠加地势和描述性土壤信息。它是一个相对系统，指的是在给定区域气候下依赖救济的土壤条件与潜在天然林关联之间的（假设）平衡。因此，气候设置应该是恒定的，并且主要基于降水和气温的长期平均值。然而，长期气候变化以及罕见的极端气候尚未得到充分考虑。此外，无法解决森林管理本身对可用土壤水的反馈。为了克服这些缺点，我们开发了一种方法，将土壤水文模型 LWF-BROOK90 组织在 GIS 框架中来模拟日常水通量和土壤湿度状态。空间分布的气象输入数据是使用特殊的区域化程序从长期站数据生成的。按层位划分的土壤物理性质的模型参数化是使用pedotransfer 函数从详细的森林土壤图导出的。因此，我们获得了水平衡所有组成部分的数据，具体取决于气候、坡向、坡度、垂直土壤特性和林分条件，空间分辨率为 25m×25m。除了场地水平衡模型的共同输出外，还实施了额外的指标来量化“蒸腾胁迫”、“土壤干旱胁迫”和“土壤水分过剩胁迫”。土壤水评估基于超过参数值定义阈值的天数。实施的土壤水分指数适合反映不同地点土壤水分条件的相关差异，而关注个体和极端年份而不是长期平均值似乎更适合评估与水相关的树木生长条件。下一步将是根据此类“压力”指标制作森林站点地图。与目前使用的绘图方法相比，这种新颖的方法可以更客观地描述可变的土壤水条件。此外，它还使空间水文数据（例如地下水补给）可用于森林管理之外的用途。
Knowledge of site-specific water conditions is important in forestland evaluation and fundamental for a sustainable forest management. In Central Europe, traditional site mapping has followed an integrated ecological approach. The assessment of soil water availability is based on overlaying relief and descriptive soil information. It is a relative system referring to an (hypothetical) equilibrium between relief-dependent soil conditions and the potential natural forest association at a given regional climate. Accordingly, the climatic settings are supposed to be constant and are mostly based on long-term means of precipitation and air temperature. However, long-term climate changes, as well as infrequent climatic extremes have not been considered adequately. Furthermore, the feedback of forest management itself on available soil water cannot be addressed. To overcome these shortcomings, we developed an approach in which the soil hydrological model LWF-BROOK90 is organized in a GIS-frame to simulate the daily water fluxes and soil moisture status. Spatially distributed meteorological input data is generated from long-term station data using special regionalization procedures. Model parameterization for soil physical properties by horizon are derived from detailed forest soil maps using pedotransfer functions. Thus, we obtained data on all components of the water balance depending on climate, aspect, slope, vertical soil properties, and stand conditions in a spatial resolution of 25m×25m. In addition to the common output of site water balance models, additional indicators were implemented to enable the quantification of ‘transpiration stress’, ‘soil drought stress’, and ‘excess soil water stress’. Soil water evaluation is based on the number of days exceeding defined thresholds of parameter values. The implemented soil water indices were suitable to reflect relevant differences in the soil water conditions between sites whereas focusing on individual and extreme years rather than on long-term averages seems to be more appropriate for assessing water-related tree growth conditions. The next step will be to produce forest site maps based on such ‘stress’ indicators. The novel approach provides a more objective description of variable soil water conditions than the currently used mapping approach. Furthermore, it makes spatial hydrological data (e.g. groundwater recharge) available for use beyond forest management.