Image 1 - Mature Sitka Spruce with pockets of natural regen, Dulverton, Somerset

 

When I first involved myself in Forestry back into 2003, one of my primary interests was sustainable forms of forestry. Much discussion and research has taken place on this broad subject over the years, and it is always good to see examples of this being successfully put into practice. In the past I had the benefit of visiting several sites, including Stourhead Western Estate, where they were further down the process of transforming their plantations to irregular structures, so for me to see those first-hand was a valuable experience.

The growing on of stands beyond conventional rotational ‘clearfell’ cycles, can in the right circumstances bring numerous benefits. It is important to have continuity of management, as these are long-term processes to implement and maintain. A change in management approach can provide opportunities to adapt to effects of a changing climate; help reduce restocking costs through utilising natural regen; improve the wider landscape aesthetics; enable the growing of higher quality larger diameter timber; increase resilience through developing irregular age structures; as well as having the opportunity to enhance species diversity with complimentary enrichment planting. Diverse uneven aged structures will increase opportunities for wildlife and benefit amenity use too.

There are various informative and practical guides available for assessing stand suitability for conversion to irregular systems, so I won’t be covering the technical elements in this post. My aim is to introduce a couple of forestry sites that are either in the process of transforming to irregular forms of silviculture or are about to start a transformative journey.

 

Site 1 - Sitka Spruce Plantation, nr Dulverton

Image 2 - Mature Sitka Spruce with pockets of natural regen, Dulverton, Somerset

The first site is mature Sitka Spruce plantation (cover photo and photo above), containing large diameter trees. In the years after the last thinning intervention, there has been very promising development of natural regen across significant areas of the plantation. There are still gaps where regen has not yet occurred, but it is reasonably well distributed. The next stage of management for this block will be to:

• establish permanent access racks for management at approximately 26m spacing
• carry out some enrichment planting with Coast Redwood, Western Red Cedar and Japanese Cedar to diversify the species mix
• monitor the development of the natural regen.

Note: The intention here is not to respace the natural regen, but to thin out with a clearing saw to retain the best young stems. After these stems develop further, they will be recruited into the stand as a second age class.

 

At the same site to the East, there is an adjacent compartment with younger blocks of Sitka Spruce and Norway Spruce. These have not yet been opened enough to create suitable conditions for natural regen to occur.  

Image 3- Spruce stand ready for next thinning intervention

Assessments of the stands look promising, so it is hoped that after the next thinning intervention this will kick-start the development of natural regeneration here too. Similarly, once the regen start the species will be diversified with some enrichment planting.

 

Site 2 – Western Hemlock Plantation, nr Torrington

Image 4- A stand of mature Western Hemlock recently thinned, Sept 2021

The second site is a mature stand of Western Hemlock, planted around the mid-1960s. The stand was conventionally thinned regularly up to a point. However, under the previous ownership a couple of thinning interventions were missed. Typically, over the years a thick needle bed has formed and with the disturbances from a reintroduction of thinning control, this should open this up sufficiently to assist natural regen. The trees are coning heavily, so it is hoped that plenty of viable seed is being produced.

The latest thinning intervention was completed only last week, and the objective was an uneven thin across the whole stand, creating more open pockets around suitable heavily coning trees of good stem form, and leaving other parts with clumpier groups of trees.

Image 5 - A stand of mature Western Hemlock recently thinned, Sept 2021

Generating sufficient levels of natural regen is important to taking this transformation to the next stage. However, we are not looking to continue with a pure stand of Western Hemlock, so the intention is to diversify the species mix with some enrichment planting to complement any natural regen.

Progress updates on these forestry sites will be provided in future posts. Comment below if you have any questions.