Tweed Forest District" was prepared. This constitutes Study No. 1 in a series of 

 background papers on resource development published by the Department of Agri- 

 cultural Economics, Ontario Agricultural College. In this report, the landscape 

 unit was introduced as a suitable unit for land-use planning at the community level. 

 In Southcentral Ontario, the detailed study of parent soil materials in the 

 Pembroke District was continued. The publication of Research Report No. 50 

 provides information on the potential of the mapped land units for agricultural and 

 timber uses, for consideration in timber management and land-use planning. 



FACTORIAL SITE RESEARCH 



Factorial Site Research covers the study of individual site factors and their 

 significance for plant growth. In contrast to Regional Site Research, only one 

 causal factor is considered at a time, and this in a more detailed, quantitative 

 fashion. Notwithstanding, each factor is considered within the framework of the 

 total site complex. 



At present, two groups of factors are under study by the Site Unit, namely, 

 soil nutrient and soil moisture. Two major objectives have been selected for soil 

 nutrient investigation; the first, to determine the relative value of mineral soil 

 materials as sources of nutrients; the second, to determine the variability of 

 available soil nutrients including those in forest humus. The three projects in 

 progress are: — 



(1) Calcium release from minerals. 



(2) Nutrient release from soil parent materials. 



(3) The regimes of soil nutrients under various combinations of vegetation, 



soil profile development and parent soil material. 

 Initially, the soil moisture investigations have been aimed at determining the 

 magnitude of water deficits and their effect on tree growth. The two programs which 

 received attention during 1963 were (1) regional soil moisture regimes, and (2) 

 moisture deficits on deep dry sand. 



SITE PRODUCTIVITY RESEARCH 



Site productivity research comprises the study of the comparative productivity 

 of different sites at various area scales and from different viewpoints, namely, 

 biological, technological, economic and social. Productivity studies include not only 

 the type of crops, and the yield in terms of quantity and quality, but also the 

 conditions and practices required to obtain specific yields. In these studies, the 

 findings of regional and factorial site research are integrated within a hierarchy 

 of scales which facilitate the various ratings required for resource management 

 and land-use planning. 



In 1963, a start was made in assembling data concerning potential site index 

 values for various physiographic site types and forest species in each of the site 

 regions of Ontario. 



During the year, a working liaison was also estabhshed with specialists in 

 wildlife research and management in order to obtain better definition of classes 

 for rating the potential of land for wildlife production. 



Silvicultural Research 



Silvicultural research units have been established in each region of the 

 province to study the characteristics of the commercial tree species and the environ- 

 mental factors which affect growth and reproduction. The object is to develop 



250 



