Global Climate Change: Setting the Context

 

Climate change: Impacts on UK forests - Chapter 1
By Mark Broadmeadow

The association between climate and forestry has been a matter of discussion for many centuries with, for example, John Evelyn highlighting the importance of water, sun and temperature to the success of plantations in his treatise to the Royal Society in 1621:

‘...Water in this action ... does not as we affirmed, operate to the full extent ... without the soil and temper of the climate co-operate’

and

‘This we find, that the hot and warmer regions produce the tallest and goodliest trees’ and ‘as is found in our American plantations, ... both since so much improved by felling and clearing these spacious shades and letting in the air and sun.’

These observations may seem outdated, but many of the modern approaches to forestry, including provenance selection and silvicultural management are based on the long-standing knowledge of the relationships between climate and forest productivity. It is therefore not surprising that there is great concern over the implications of a changing climate to the forestry industry, particularly since the species and provenances planted at present and in the recent past reflect the current climate. There are also a number of species important in ancient and semi-natural woodlands which are close to or at their climate limits, and thus conservation and biodiversity benefits may be threatened. Among the questions that need to be answered (and asked in some cases) are:

• Will the species and provenances currently planted survive under a changed climate?
• Will forest productivity change (for the better or worse)?
• Do management practices need to change?
• What are the consequences for habitat action plans?
• Are conservation and recreation benefits threatened?
• Can forestry play a significant role in counteracting climate change?

These questions are not easy to answer. Firstly, we do not know what a future climate will bring. Secondly, even if we could secondguess the climate, predicting the weather and, most importantly, the extreme events such as droughts and storms, is not possible. Finally, it is difficult to make integrated assessments of the impact of climate change on the complex processes and interactions present within forest ecosystems.

Next: Chapter 2 - The changing climate of the UK: now and in the future