Abstract

The Taiwan Red- and Yellow-Cypress are the most important coniferous trees of Taiwan and producing ideal construction timbers of particular usefulness in subtropical countries for anti-termites. Unfortunately these valuable trees, for some reasons or the others to be studied, are now tending to be exterminating. Hence the following problems call for a critical study; 1. Why is Taiwan Cypress endemic to Taiwan and not occurred in any other part of the world? 2. Why are they now exterminating? 3. How to maintain proper forest management and adequate silivicultural method to reserve these valuable species? The summaries and conclusions of the ecological and silvicultural studies of the above problems are as follows: 1. Peculiar climatic conditions occurred in this particular region having a combination effects of high relative humidity, cool temperature, moderate high annual precipitation, and the influence of prevailing typhoons, are the factors controlling the distribution area of these species. 2. Taiwan Red- and Yellow-Cypress are light demanding species. The thick and luxurious undergrowths of the forest floor impeding the fallen seeds in germination and growth and the cutting away of Taiwan Cypress in all the accessible regions and leaving too many over-matured trees bearing no more seeds for natural regeneration in all the accessible places cause a tendency of extermination. 3. The over-matured stands of forest should be cut off in a period of 120 years instead of 40 of the present management plan and to regulate the age classes to the "Normal Forest", so that the rate of growth and drain shall be balanced and matched up with the 120-year rotation. 4. Artificial reforestation with seedlings raised from seeds of selected mother-seed trees is the only measure of conserving these valuable species from extinction.