Forest Methods: Revised Japanese and English Translations of Sai On's Somayama Houshikichou(杣山法式帳) (Collected Provisions Related to Mountain Forests)

The contents of‘Forest Methods' can be divided into three main sections: the classification of mountain forest terrains, the care and administration of forests and descriptions of different mountain forest types, with eleven articles out of the main 19 articles devoted to mountain forest terrain.‘Forest Methods' begins with a discussion of terrain analysis. It divides terrain into steep mountain slope and gentle mountain slope categories and discusses the merits and demerits of surrounding mountain forest conditions including the height differences and relative distance between mountains. The purpose of this is to outline the criteria necessary in order to assess the most appropriate locations for forest planting. The first main feature of‘Forest Methods' relates to the ideal configuration of terrain for the purpose of preserving the essential energy (qi) of the mountain forest, or‘sanqi'. The most important concept outlined therein is that of‘embraced protection' (hougo). In‘Forest Methods', embraced protection is described as“the condition in which surrounding mountains serve to prevent the loss of mountain forest qi". This ‘embraced protection' concept can still be utilized today in bringing about environmental improvements to rural and urban areas by developing techniques that preserve qi through strategic tree planting. Such techniques were applied in early-modern Ryukyu, including roads lined with Ryukyu Pine trees, forested areas of embraced protection strategically planted to surround a village, trees strategically planted to provide embraced protection along stretches of coastline and Fukugi trees strategically planted to surround individual residences. The second main feature of‘Forest Methods' is an emphasis on the importance of preserving qi from the perspective of forest care and maintenance.‘Forest Methods' stresses that if trees are cut down or burned down at the most critical place in the forest, known as the‘gate of embraced protection', where the tips of the ridge-lines of the embraced protection mountains overlap just like the collar of a shirt overlaps when fixed, wind can enter through such man-made gaps and ultimately this will lead to the ruin of the forest. In order to preserve this vital mountain forest qi,‘Forest Methods' instructs that thorough maintenance work for the protection of the forest be focused on the gate of embraced protection. The third main feature of‘Forest Methods' is the use of illustrations for the purpose of teaching the reader how to understand different types of mountain forests. The illustrations are of an Itajii(castanopsis sieboldii)forest in the northern part of Okinawa Island. They show forests at progressive stages from the initial growth phase through to maturity and also the impact of human involvement by showing the condition of forests in the aftermath of tree felling. Commentary is provided alongside each illustration.この「杣山法式帳」の内容構成は、杣山の地形の見方、杣山の保育・管理の仕方、山の林相の見方の３部から成るが、全１９項目のうちの１１項目は、杣山の地形解析に当てられている。まず山の地形を大きく、急斜面から緩斜面に分け、その地形を取り囲む山の状態(山の高低差や遠近)の良否を論じている。その目的は、植林するときの適地を判断する基準を示すことにある。その特徴の第１は、山の気を保全するための地形の配置を論じている点にある。その中で重要な概念として提示されているのが、抱護の考え方である。「杣山法式帳」では、「山気が洩れないように、山々が取り囲んでいる状態」のことを抱護と規定しているが、この規定はさらに都市や農村の環境整備に応用されて、植林による気の保全の技術へと発展していく。近世琉球における街道沿いの琉球松並木、集落を囲む村抱護の林帯、海岸沿いの抱護の林帯、フクギの屋敷林などは、その応用事例である。この法式帳の第２の特徴は、杣山の管理の面での気の保全の重要性を説いている点である。抱護の山々が重なっている稜線の先端が、衣装の襟を重ね合わせたような所を、伐採したり、焼き明けたりすると、そこから風が吹き込み、終いには山が荒廃してしまう、とこの法式帳では強調する。山の気を保全するためには、抱護の閉じ口の森林の保全管理を徹底して行うよう指示している。この法式帳の第３の特徴は、山の林相の見方を図で例示している点である。その図は沖縄本島北部のイタジイの森をイメージして書かれているが、成長の初期段階から成熟した森、さらに人間によって抜き切りされた状態の森林などについて、それぞれ図で示しながら解説している