Is Screefing Worth It? Time for a scientific review

Planter DrawingSilviculture contractors are saying it is time to do a scientific review of the advantages of planting seedlings in contact with fermenting forest soil (F layer). By reducing if not eliminating “screefing” seedlings to a greater soil depth, as required by the ministry of forests, mines and lands’ planting standard (FS704), contractors say F layer planting would increase productivity, reduce worker injuries and grow better trees.

Since the early 1990s some industry licensees and the ministry have planted trees using diverging methods. There have been particular differences around the depth of planting and the retention and contact of roots to the F layer of the forest soil. Instructions have also varied regarding what is an acceptable planting site, how much “screefing” off of organic materials is required and where seedlings can be placed relative to other planted trees and the best planting spots.

The Western Silvicultural Contractors’ Association says there are in effect two planting systems being used in the province: the F layer and the FS704 standard. The association says there is anecdotal evidence that the F layer plantations are doing better than those planted to the FS704 standard. Trees planted in the F layer, particularly if the planter puts them in softer, higher and warmer sites, have a better chance to develop vigorous roots. This is why they grow better say contractors.

At the same time planters working to the F layer standard do better as well say contractors. In an industry with a very high rate of musculoskeletal (MSI) and repetitive strain injuries already, reducing the amount of work needed to plant a seeding, i.e. screefing, will improve worker health, increase productivity while reducing injury claims and costs.

Differences of opinion over the two standards have led to conflict and antagonism between contractors and the ministry over what are properly planted seedlings. The contractors want to see studies set up to review the science and results of F layer planting as part of a proposed review of the ministry’s whole tree planting inspection system and standard. At the same time the BC SAFE Silviculture Project is beginning a major strategy to reduce injuries due to hard work in the silviculture sector. It will include investigating the effects of screefing on workers.