Orchard light environment analyzing system (OLEAS)

Crossings of beams of oblique-square pillar (BOSPs) against internal cubic blocks in a virtual grid (VG) gave a possibility to analyze in accordance with Monsi and Saeki's theory (1953) light environment in an isolated fruit tree crown where leaves did not distribute at random to the horizontal directions. Some partial corrections of the model's parameters and improvements of the work of simulation were made on the previous model (Yamamoto, 1988). The tests of the modified model (SCLEAS) produced good results. By extending the functions of the SCLEAS from a single fruit tree to an orchard, a new system (OLEAS) was developed. The use of the OLEAS was limited to orchards where fruit tree crowns having an identical shape and canopy structure were arranged with an arbitrary planting distance. The distance between the predicted fruit tree and the neighbor trees, namely, tree space and row space, should be integral-fold of length of a side of the block in the VG. By the procedure, in the spaces of outside of the predicted VG the OLEAS can utilize repeatedly a set of data from the crossings, namely, Vr values (ratios of the volume of a solid cut by both a BOSP and xyzco-ordinates to the volume of a block) and these block positions, which are calculated once in the predicted VG. When the altitude of parallel beam (Ho) is greater than 45, the range of surrounding fruit trees which have actions of light extinction on the predicted tree is limited to the 8 neighbor trees against all azimuths of the beams (Azs), and the 3 neighbor trees against an Az. When Ho is smaller than 45, a vertical plane of entrance of BOSPs is set at the distance which is integral-fold of G in the horizontal direction from the side of the predicted VG and also is longer than the shortest distance where any light extinction by the surrounding trees does not occur. By the procedure a set of data of the Vrs and the block positions can be used repeatedly every time a top of BOSP moves the distance of G. Algorisms to judge whether a top of BOSP stepping down along z axis exists within the predicted tree or a surrounding tree or the other space are devised in the 2 cases (Ho=45 and Ho45) using several simultaneous unequalities. If a top of BOSP exists within a surrounding tree, the OLEAS make a parallel translation of the grid covering the tree to overlap completely to that of the predicted tree. The cumulative leaf area index from the entrance of BOSP to the top (L') is calculated using leaf number per block of the top. This leaf number per block is given by reference to the value of array of distribution of leaf number (B (x, y, z)) of the corresponding position in the predicted VG after the translation. Because the OLEAS has the same principle as the SCLEAS, the OLEAS is thought to have the same effectiveness as the SCLEAS. The work tests of the OLEAS produced good results against many orchard models which were constructed by arranging the several fruit tree crown models with 8 planti