MODEL OF A REGULATED FOREST 

 By D. Y. Lin, M.F.* 



A mechanical model designed to show the growth of a forest 

 imder regulation was built and has been used for lecture work by 

 the Lecture Department of the National Committee of the Yoimg 

 Men's Christian Association of China. The model is like the one 

 described in Forestry Quarterly, Vol. XII, No. 4, very much 

 modified and improved. Professor C. H. Robertson deserves all 

 the credit for having improved the mechanism. Since the first 

 lecture series on conservation of forests was given here, in Shanghai, 

 some time during last June (1915) as many as 32,000 people have 

 seen the model, and, as a part of the lecture equipment it has 

 always formed the centre of attraction. 



The model shows a series of ten areas, each a different age 

 class, ranging from one to ten. When in opeartion, the stand on 

 each area will slowly grow taller until the end of the rotation when 

 it will disappear and a new crop start on the depleted area. The 

 starting of a new crop on the depleted area represents planting 

 and this is to follow immediately after cutting in order to get 

 the proper results. 



The incentive for making such a model was a desire to visualize 

 to the people looking on a growing forest and convey the idea of 

 how a forest under systematic management can be harvested at 

 regular intervals and at the same time produce continuously. 



We have found that the model is a great help to us in our 

 lectures. People who are interested in the model will always see 

 the points we want to demonstrate. We mention this to show 

 that the model is worth while and well worth having, especially 

 in schools where forestry is taught. 



The model is V 27/' long, 19" wide, and 14" high. It has 

 adjustable legs of 2V2' to 4' high and these can be removed 

 when the model is not in use. Each of the ten areas or stands 

 consists of a galvanized iron plate with "trees" fastened to it. 

 The plate is 17" by 7" and the "trees" are arranged in seven rows, 

 ten trees in four rows and nine trees in three rows, making sixty- 

 seven trees in all for each area. The "trees" are made of hemp 



1 Secretary, Conservation Division, Lecture Department Committee, 

 Young Men's Christian Association of China, Shanghai. 



471 



