The afforestation programme at Kielder is virtually nil but in order to sustain further production around 750 hectares are restocked each year. The hostile upland environment of Kielder is not suitable for growing any broad-leaved tree species as a commercial crop. Only 2% of the forest is presently broad-leaved, but the current planting of approximately 100,000 broadleaves a year will rise to 8%.
Of the conifers Sitka spruce is the most productive and most economic species to grow across virtually all of the Forest District. It currently accounts for 70-80% of the conifer element. In light of the uncertainties as to the future of the climate and the likelihood of an increase of pest and diseases, the Forest District aims to increase the diversification of suitable species. Other planted conifers currently include Norway spruce, Scots pine and Douglas fir, and whilst these are grown for timber production, they also add value for wildlife and amenity.
Many of the soils at Kielder are not highly fertile so weed competition is not a great problem, the natural regeneration of dense patches of Sitka spruce is more of an issue. For this reason, on the non-weedy sites we aim to leave a three year gap between felling and restocking to allow us to assess the levels of regeneration before planting. The more fertile, weedy sites tend to have less natural regeneration, so we aim to restock these in a shorter period of time after felling.
Site preparation prior to planting varies and is designed to be as cost-effective as possible, under the following guidelines:-
- Until recently it was considered essential to fence all restock areas against Roe deer. Local research suggests that Sitka spruce can be established without fencing, with concentrated Ranger input to shoot deer on these sites. As all other species are slower to establish and are more palatable to deer, fencing is required.
- Trees need to be planted on dry ground where their roots are not constantly waterlogged. To prevent asymmetric root development (which may lead to instability in the crop in later years) it is important that the trees are not planted hard up against the old stumps. On previously ploughed ground it is not a problem – the trees are planted on the old plough ridges mid-way between the old stumps. On well drained, unploughed sites, often the only “raised position” is immediately adjacent to the old stumps. On these sites it is sometimes necessary to create a mound of soil/peat on which to plant each tree. This can be carried out by digging individual mounds (one hole for each mound) or, and in particular where a lot of drains are required, by “ditching and dolloping” – the digging of drains and use of spoil material to create mounds. Individual mounding is also used as a method of weed control on more fertile sites.
- Present harvesting methods often leave strips of thick, hard-packed brash on site that cannot be planted through. If not planted these strips result in a large proportion of the subsequent crop being too widely spaced creating unacceptable large and heavy side branches (producing low quality timber). Brash raking is carried out on these sites to concentrate the brash and enable a more uniform distribution of the correct number of trees.
- On the majority of sites it is necessary to put in some drains to either remove water or prevent it from getting onto the site. The drains are put in at the same time as other site preparation work, and are normally at a density of around 100m per ha.
All the above operations (draining, brash-raking and mounding), together with operations such as pond digging can be carried out using a tracked excavator. This work is done by contractor in a package of work for each site.
Plant treatment/plant handling and planting
Before being planted all conifers are treated with an insecticide Alpha Cypermetherin as protection against bark-eating Hylobius beetles (permethrin is a synthetic pyrethroid – a man made copy of a natural insecticide found in the flowers of a type of Chrysanthemum – the pyrethrum).
Treatment is carried out by electrodyne treatment using Alpha Cypermetherin. The chemical is then allowed to dry onto the tree prior to planting. Once dried the chemical becomes “fixed” onto the tree and will not be washed off by rain.
All young living things: plants, animals, babies, need to be handled with care if they are to survive and grow well. Careful plant handling (taking care not to drop, squash, desiccate etc.) means the difference between planting a tree that is struggling to survive and can easily succumb to pressure from weed competition, deer browsing, insect attack, waterlogging etc., and one that is healthy, full of energy and raring to go.
Planting, carried out when trees are dormant during the winter (or spring if they have been kept in cold store) is at a density of 2500 per hectare. Some 95% of the 2 million trees planted at Kielder each year are planted by contractors.
Broad-leaved trees and shrubs are planted to enhance amenity, conservation and wildlife. They are planted 4-5 metres apart in small multi-species groups. Most are native species and are planted according to site type, matching the planted species to what we would expect to occur on the site naturally (e.g. willow and alder in very wet areas).
Planting is designed to create mixtures of planted and open ground, shade and shelter, large wide crowned trees and low, sometimes dense, shrub areas. The most common location is along stream sides and adjacent to open areas and ponds. There is no intention to harvest these trees.
Maintenance and after care
Our aim is to plant a site before it becomes too weedy with strong vigorous plants, when necessary protected by a fence. When this works the after-care is minimal, although some dead trees will require to be replaced (“beating up”) two years after planting. A few areas require weeding and this is done as and when necessary with the most appropriate chemical.
If an area has naturally regenerated with Sitka spruce it is unlikely that the trees will be at the right spacing to produce the type of timber that we need (too close and no sawlog material is produced, too wide apart and timber quality suffers). It is therefore often necessary for remedial action to be taken.
If the trees are too far apart, then they will be beaten up in a similar way to an understocked planting. If they are too close then it becomes necessary to respace them out to no more than 2m spacing. The timing of this operation is critical: too soon and it may need repeating, too late and the cost becomes too high and there is a danger of the trees that are left becoming unstable.