Sub Compartment Assessment Record Card
Card is courtesy of Inverness, Ross and Skye Forest District and staff at their Fort Augustus office.
These cards were filled in during the 1970s following the resurvey of a forest by the Forestry Commission Survey forester teams trained for the purpose. Before the advent of computers these cards were designed to aid interpretation of data. The details of each individual sub-compartment (the smallest identified unit in a forest and part of a compartment) are written on the card but also in a coded form around the edge of the card via a series of holes which can be clipped through. The chamfered top right hand corner ensures that the cards can easily be checked to ensure that are aligned correctly. The theory was that large numbers of cards could be taken in hand and by inserting a needle into the appropriate holes all the cards which had been clipped at that hole would fall through. For example if you were looking for Sitka spruce in a forest you would insert the needle in the appropriate hole on the bottom (SS) and shake out. Should you then be looking for a certain yield class in the Sitka spruce then the procedure was repeated using the Yield Class in the already sorted cards.
In a large forest, or one where some amalgamations had taken place, the number of Compartments could well be significantly in excess of a thousand or even three. The number of sub compartments within each compartment varied enormously from one to over fifteen but certainly two to five were very common. In all, this added up to a great deal of cards which were housed in little metal drawer boxes 10.5 inches wide each holding perhaps fifteen hundred or more cards (See PDF).
In reality sorting by needle was a tedious procedure and seldom used. The first computers were by this time available in Head Quarters and once the data was laboriously manually added they were able to print out the growing crop data for the whole forest in fan fold paper. They could also run simple timber harvesting forecasts which was always the principal aim. As Scotland’s national forest matured and the volumes of timber harvested began to increase there was a critical need to secure an efficient system of forecasting and establishing a total timber cut that was sustainable and appropriate to the growing tree crops. The forest surveys established a much more accurate database on which to base all the calculations and over time the computerised forecasting systems were able to take into account the different species, different growth rates, no thin and thin policies, 5 year and 10 year delay in first thinning cycle, different crop spacings at time of planting, line thinning and many other local variations such as thinning cycles of 5 or 7 years etc. No matter how slick the system became accurate growing stock data was always critical.
The PDF shows the reverse of the card which were seldom filled in.