Study of evaluation of natural environment preservation by the measurment of the natural environmental sound

我们认为，所有的声音都被重新视为“环境声音”的研究。然后，通过种类将“环境声音”分为“生活环境声音（人工声源）”和“自然环境声音（非人工声源）”。特别地，对于“自然环境声”的观测案例很少，目前一般没有确定观测方法和评价方法。噪声测量用于天然森林（自然环境的丰富空间）中的自然环境声的观测。此外，还通过树木的解剖和地形调查，对声音结构进行了研究。采用易于与生活环境声进行比较的等效噪声级作为自然环境声评价值，在调查适用区域内设置3个观测点。从三个定点观测的结果中，我们可以掌握等效噪声水平的一个特征和方差。根据这些结果，提出了指数化的可能性。在森林合理结构的把握上，通过对林学领域树木普查调查林分的分析，提出了聚类的可能性。

We take a position that all sound is reconsidered as "an environment sound" by this research. Then it is separated "an environment sound" into a "living environmental sound (artificial acoustic source)" and a "natural environmental sound (non-artificial acoustic source)" by a kind. Specially, there were a few observation cases for the "natural environmental sound", generally an observation method and an evaluation method aren't decided at present.A noise measurement is used for the observation of the natural environment sound in the natural forest (the rich space of the natural environment). In addition, it is investigated about a sound structure by a tree cesus and a topographical survey. The equivalent noise level which was easy to compare with a living environment sound was adopted as a value of the evaluation of the natural environment sound.Three observation points are installed in the investigation applicable area. We could grasp a characteristic and a variance about the equivalent noise level from the result of three fixed-point observations. By these results, the possibility of index-ization was suggested. About grasping of the sound structure in a forest, a possibility of clustering is suggested by an analysis of the forest stand which was investigate by the tree census in field of forest science.