Establishment and early growth of different plant types of Corsican pine (Pinus nigra var. maritima) on four sites in Thetford Forest

Abstract

The field performance of six different plant types of Corsican pine (Pinus nigra var. maritima (Ait.) Melville) was compared over the first 4 years after outplanting at four sites in Thetford Forest, East Anglia. The stock types differed in size, age and method of production and included conventional 1-year-old container seedlings raised in Japanese Paper Pots and Rigipots, 1 1/2 - and 2-year old seedlings raised in Japanese Paper Pots, as well as 2-year-old bare-root seedlings which either had or had not been undercut. Survival was high (> 87 per cent) for all types except the non-undercut 2-year-old bare-root seedlings. Height and stem diameter growth were generally low during the first year after planting, but by the end of the second year there were significant differences between individual plant types and sites. Analysis of height increments in the second year suggested that the 1 1/2 -year-old container seedlings raised in paper pots had recovered from planting check, whereas other stock types had not. However, average increments were not great enough to allow these 1 1/2 -year-old seedlings to overtake 2-year-old seedlings which were taller at planting. All stock types had apparently recovered from check in the third and fourth years after planting and were tending to grow on the same growth curve at each site with shorter seedlings producing smaller height increments. Thus initial seedling size and site factors, rather than method of production, were the most important factors determining future growth with the height advantage of taller seedlings at planting being maintained or increased in subsequent years.