We wanted to keep our use of herbicides to a minimum so we knew weed control was going to be difficult. In particular we banned residual weedkillers that could have harmed the rare bryophytes in the nearby Site of Special Scientific Interest. As a result the smaller and slower growing trees battled to survive against the weeds and we lost nearly all of our corkbark fir, Abies lasiocarpa var. arizonica. We were avoiding pesticides wherever we could, too, and in 1996 we had a serious problem with the potentially devastating green spruce aphid on the blue and Norway spruces. There is still no commercially available biological control for this pest so unfortunately we have no choice but to use a pesticide - but luckily were able to use one that only kills aphids.
Pruning the trees with shears may be labour intensive but it is almost
essential nowadays for growers who want to produce the best quality trees
so it was an important part of our trials. The technique and timing varies
with each species. Spruces are sheared in the winter to a 60 degree angle
and with a leading shoot no longer than 35 centimetres. In the summer before
harvesting unwanted shoots are pinched out with fingertips, as shearing
would cause unsightly browning of the cut needles. Pines are pruned in early
June after they have stopped growing and while the buds at the base of each
pine needle have a chance to grow to cover the pruning scar. The firs are
the most difficult to prune because if the leading shoot is pruned or damaged
the new shoot arising from a dormant bud is seldom straight. Fraser fir,
however, has plenty of buds and can be sheared almost like a hedge in July.