12 KERRY WOODS. 



been grown. The trees which would be removed are termed the 

 minor crop. Such a division is necessary where woods are 

 thinned at irregular periods if the results of an investigation are 

 to be of any use for comparative purposes. The volume cal- 

 culated in this way makes no great pretence to accuracy, since 

 it is difficult to select with precision a sample tree fully repre- 

 sentative of the mean tree of the crop. 



By felling a greater number of sample trees the volume may 

 be calculated with greater accuracy, but in the present case this 

 was impossible. The volume is, unless otherwise stated, given 

 as true volume including bark. 



Each of the species examined will now be dealt with in turn.* 



A. Larch. 



For the investigation into the growth of larch, there was a 

 great deal of material available, both young and mature woods, 

 in sheltered and in exposed localities. 



In consideration of the facts that the development of larch is 

 poor here in exposed localities and that the mature woods are 

 not properly stocked, it was decided to measure a series of 

 groups at various elevations in a wood known as Cwm Golog 

 20-24 years old, and to check the height-growth development of 

 the group sample trees by felling other sample trees among the 

 maturer crops at various elevations. 



Cwm Golog occupies a steep northern slope and is sheltered 

 in its lowest parts both to the east and the west by flanking hills. 

 The original crop was obviously a mixture of larch in lines 8 feet 

 apart filled up to 4 feet with Scotch pine, spruce, silver fir, and 

 Corsican pine. The larch has grown so vigorously, however, 

 especially in the lower parts, that all the other species have been 

 killed out and a pure crop is the result. This point is referred to 

 again later. 



The following is a description of the various groups : 



GROUP Lit 



Area, 0*3 acre. Elevation, 975 feet. Age, 23 years. 

 This Group lies at the foot of a steep slope on deep well-drained 



* Most of the sample areas were girthed at breast height in the first instance, 

 but it was considered more suitable to rely on caliper measurements, and the trees 

 were consequently calipered after a year's growth had taken place. These latter 

 figures have been utilised in applying the formula \ = Afh. The value of the form 

 factor is taken as that of the previous year. 



The increase in height during the year has been read off from the height-growth 

 curves of the sample trees. In most cases, therefore, it will be noticed that the 

 value of h used is slightly greater in the formula for calculating the volume than 

 for the sample tree. 



t Details are given of the stem diameters for each sample plot in Appendix B., 

 PP- 54-58. 



