Benefits of plantation thinning are clear to see

Joe Barry

July 30 2013 04:03 AM

With only two years of forestry premiums remaining, I am more focused than ever on ensuring that my woods continue to pay.

The ash and sycamore here in Meath have been thinned gradually for a number of years and are really showing the benefits of what some would describe as over intensive management but which I would prefer to call plain common sense.

With a grant available for first thinning and a ready market for the timber harvested, it would be wasteful and negligent not to make full use of these bonuses.

As the trees continue to grow I am more convinced than ever of the importance of keeping ash well spaced. Unlike many other species, it is hungry for light and must be managed accordingly.

We are all concerned regarding the possibility of damage from Chalara (ash dieback) and other diseases, but this is no excuse for not continuing to care for our woods.

The various strains of Phytophthora that threaten almost every tree species are also a real danger but we cannot use this as a reason for not managing our young plantations.

Just like other plants and animals, healthy trees provide the best possible natural resistance to diseases and keeping them in top condition represents our best chance of avoiding losses.

I have also thinned all of the larch and created racks through the oak and beech mixes.

Oak and beech need lighter interventions as over-thinning only produces abundant side shoots that then require removing.

Light management is a skill that I am trying to learn and to do so, I have tried different systems over the years.

Having been advised to leave the oak alone for approximately the first 30 years and only then commence thinning, I am sticking, more or less, to these principles but at the same time keeping an open mind while monitoring their progress.

Each species has its own specific needs and we are continually learning what suits best within our own woods.

TRIAL

We cannot blindly follow the management practices that suit other countries but must learn what is best by trial and error. Soil and microclimates can vary hugely, even on just one farm. Again, we must let the trees teach us what is best by observing their development closely.

This means carrying out frequent inspections within our own woods and also visiting others to make comparisons.

The conifers in Leitrim have just had their first thinning and while it can be alarming to see the damage that large harvesters and forwarders can inflict on the ground beneath them, at present I can see no economic alternative to this method.

Were the trees close to our firewood yard in Meath I would have tried thinning them the same as we have done with our broadleaves – by using chainsaws for felling and the quad with mini crane and trailer for extraction.

To do so 70 miles away and then transport the timber back home was simply not an option. The timber will be sold locally and when the final figures for expenditure and income have been assessed I will write on them in more detail.

If our woods are to stay they must pay, and my long-term objective is to allow natural regeneration to provide the next crop.

Replanting is costly and I want to create a situation where just a limited number of mature trees are removed annually, eventually evolving into a mixed age, mixed species woodland.

Already there are thousands of young ash, sycamore, cherry, maple, oak, beech and many others growing rapidly where the increased light following thinning has allowed them to become established.

This mix of species must surely give us a better chance of avoiding a disease epidemic in the future.

Despite some concerns, I think that this could well pay handsomely in the long term.

While being cost-effective, by avoiding clearfell, it will also ensure that the farm continues to benefit from the shelter the woods provide and my successors can enjoy the beauty of a semi-wooded landscape for centuries to come.

The landscape and environmental benefits of this type of management are huge and as we also use our woods for leisure as well as profit, it certainly seems the best option.

I intend to continue thinning selectively and manage the trees to what I hope is their best advantage. If I am still around in 20 years' time, I can then finally assess the merits or otherwise of encouraging regeneration without incurring any loss of income.