Many trees emit a scent or fragrance.  They form volatile organic compounds (VOC’s), often oils.  Pine trees, for example, release pinenes. Such VOC’s contribute to the smell that you may experience as you walk through a woodland.  The VOCs contribute to the formation of aerosols.  An aerosol is a ‘mixture’ of very small particles (solid or liquid) in air; other examples of aerosols include mist, cigarette smoke, or even car exhaust fumes!  Recent research by the University of East Finland has showed that aerosols formed from VOCs can reduce the amount of solar radiation that reaches the earth’ surface, by scattering some of the radiation back into space.  [caption id="attachment_40200" align="aligncenter" width="532"] Felling in progress[/caption] Pine trees are often grown in vast numbers and periodically felled for timber and paper making.  One by-product of paper-making (by the Kraft process) is turpentine - formed by the condensation and collection of the volatile oils in the wood). The pinenes (α and β) are major constituents of turpentine.  ‘Turps’ is used as a solvent to thin oil-based paints, for producing varnishes and as a ‘raw material’ in the chemical industry.  α-Pinene was used to make toxaphene (an insecticide, now banned).  Pinene can also treated with acetic acid to make a perfume with a pine needle smell. Recently a team of scientists at the University of Bath have found a new use for the by-products of paper production.  Using pinene from turpentine, they have been able to make a number of pharmaceutical compounds that can then be made into the painkillers - paracetamol and ibuprofen.  They have also successfully made other chemicals from the plant based turpentine, including compounds that may be used to synthesise `beta-blockers (heart tablets) and salbutamol (used for asthma).   At present, many pharmaceuticals and other chemicals are ultimately derived from crude oil.  Hopefully, this research will ultimately lead to a more sustainable and ‘green’ approach to drug / pharmaceutical manufacture. Biochar is the black residue, consisting of carbon and ashes that remain when plant biomass is subject to pyrolysis - that is, very high temperatures with very little  or no oxygen present oxygen. The material that remains is largely elemental carbon.  The benefits of converting plant biomass into biochar is that the carbon is ‘locked up’, rather than being released by decay and decomposition into the atmosphere as carbon dioxide.  Its advocates claim that when added to soil, it improves soil structure and function, as well as being a form of carbon sequestration.. [caption id="attachment_40215" align="alignleft" width="300"] cocoa fruit[/caption] Various forms of biomass (woody debris, corn stalks) have been used to produce biochar, however, a novel method makes use of ‘discarded’ cocoa bean shells.  These are heated to a temperature in excess of 600oC, with no oxygen present.  This particular form of biochar is being produced in in Hamburg. The plant, which is one of the largest in Europe, receives a supply of used cocoa shells viably a network of grey pipes from a neighbouring chocolate factory.  Apart from its use as a fertiliser, it is possible that it might be used as an ingredient to create a ‘green’ (or more environmentally friendly) form of concrete. The sequestration of carbon is vital if we are to avoid the worst effects of climate change.  Global warming has triggered an increase in heatwaves, floods, droughts, and forest fires in recent years; June temperature data confirms it was the planet's hottest on record. Cocoa fruit : courtesy of Pixabay.

We first became aware of the tree health pilot (THP) scheme in 2021 when we received a Statutory Plant Health Notice (SPHN) for trees infected by one of the specified pests. The THP scheme has been designed to help slow the spread of pests and diseases affecting trees in England. There are grants available for larch trees with Phytophthora ramorum, spruce trees affected by Ips typographus, sweet chestnut trees with Phytophthora ramorum or sweet chestnut blight, oak trees with oak processionary moth (OPM) and ash trees with ash dieback. In our case, the Larger Eight-toothed Spruce Bark Beetle [Ips typographus] had been found in the Norway spruce and we were instructed to fell, move, process and destroy all spruce trees in the defined area of the wood. Strict but clear directions were given regarding the ‘how, when and where’ for the felling and processing. An initial site visit and ongoing support from the Forestry Commission and their Plant Health Forestry Team allowed us to follow the process of applying for a THP grant with ease. We submitted the application and received confirmation that the grant application was successful, at which point it was over to the team undertaking the felling. Once complete a final inspection from the Forestry Commission took place to ensure we adhered to the agreed method statement (as specified in the SPHN) and then we were able to submit the claim. This claim was processed and received – all within approx. 3 weeks. Fast forward to 2023. One of the woods we are managing in the southeast (which lies within the Ips typographus demarcated area) has a small stand of Norway spruce (approx. 0.5 hectare). Some of the trees are damaged, stressed or dead, and at risk of providing the right conditions for the eight-toothed spruce bark beetle. Advice from the Forestry Commission is: How does felling healthy spruce help the situation? This reduces the opportunity for colonisation [of the beetle] and may sometimes be required as a precaution to ensure that trees that could be potentially infested are removed. Removing spruce as a host from the demarcated area entirely will limit the possibility of populations of Ips typographus establishing and prevent spread to other areas. Predicted climate change means that what is currently healthy spruce may not remain so over future years, hence early felling could reduce the risk of these areas becoming future outbreak sites. We decided to investigate whether the THP scheme could support the proactive felling and extraction of the Norway spruce. We submitted an Expression of Interest for the THP scheme, the Forestry Commission undertook a site visit and were able to confirm there was no Ips found in the wood, and we were eligible to apply for the grant. We concurrently applied for a felling licence to clear fell the compartment of Norway spruce. It is worth noting, if an SPHN is served then normally there are no restocking conditions applied however restocking and maintenance grants are available to support restoring woodland In this case there are restocking conditions in line with the felling licence – an opportunity to plant and enable native broadleaves to thrive – that can also be grant-aided. An application for the THP scheme was submitted and we subsequently received a grant offer which was accepted. What next? A pre-felling survey was required in order to determine pest freedom for Ips typographus, and the authorisation for harvesting operations remains valid for 3 months. [caption id="attachment_40238" align="aligncenter" width="675"] Galleries formed by the beetles[/caption] An inspection for Ips typographus will need to take place before any felled timber can be taken off site – the advice is to fell and move the timber quickly rather than leaving stacks in the wood. The felling commences this week and should only take 5 days, and we plan to restock with native broadleaves over the winter. The Forestry Commission has produced a very useful guide Ips typographus: Guidance on the movement restrictions of spruce trees - Forestry Commission (blog.gov.uk) but throughout the whole process the Forestry Commission and Plant Health team have been really supportive and quick to answer queries about Ips, the THP grant scheme and the forestry operations. My advice if you have a stand of Spruce – is to speak to your Forestry Commission Woodland Officer about getting involved with the Tree Health Pilot scheme or visit their website to find out more: Tree health pilot scheme - GOV.UK (www.gov.uk) Last week we hosted a number of people from the Forestry Commission, the Plant Health Forestry team, Forest Research, and DEFRA. They are continually evolving the scheme to understand how best to provide this vital funding to woodland owners to enable and encourage management of spruce and Ips. We were pleased to say they have, however,  not found it in the wood!

Recently, the IUCN (International Union for the Conservation of Nature) carried out a survey of the state of trees through Europe, specifically related to their risk of extinction.  There are some four hundred native tree species spread across Europe.   Trees are not just essential for life on Earth (generating oxygen through photosynthesis) but they also provide food and habitats for hundreds of species - birds, mammals, insects, spiders etc. The loss of tree species has considerable ‘knock on’ effects in terms of the biodiversity of an area. Trees also provide us with timber and other materials (cork, cellulose, oils). Read more...