This morning,  the Today programme (Radio 4) featured an interview with Kevin Martin ( Head of Tree Collections at Kew) and Chris Packham (environmental compaigner).  They were explaining the ongoing effects of this summer’s hot and dry weather.  Mr Martin said that the trees at Kew were “ tired, they have had a stressful summer”.  The result is that many trees are entering their dormant stage, moving materials from aerial regions to the roots - much earlier than usual.  The colour changes in leaves and leaf drop do not usually occur until well into October but this year such changes are already  proceeding apace.  Kew has been able to put some mitigations in place, for example, the watering of young trees which have yet to establish extensive roots systems. This is not true for trees across the UK, where young saplings in particular may have been affected by the dry weather and successive heat waves, [plus increased browsing by the extensive deer population]. Chris Packham spoke of “climate breakdown” and “environmental chaos”, noting that an oak tree near him was ‘festooned with acorns’, but they were only the size of peas.  Normally acorns would fall later in the year as food for wood pigeons,jays, squirrels and badgers.  Jays help ‘plant’ oak trees by distributing acorns.  He said that whilst local hawthorns were red with berries, which would normally be food for winter thrushes later in the year, the berries would now be dried up / shrivelled when the birds arrived to search for them.  Though lots of hedgerow fruit [e.g. sloes, rose hips, blackberries] is being produced, it is being produced at the wrong time.  He also commented on the scarcity of mole hills as moles are forced to burrow deeper in the soil in search of earthworms etc. As the seasons change, some plants and animals adapt. For example,  blackcaps from Northern Germany fly to the UK rather than Spain to overwinter.  During a relatively short period, their wing length has changed, actually shortened - a case of evolution in action.  However, many species are struggling.   The  wet summer of 2024 was particularly difficult for butterflies, as evidenced by the data collected by the Big Butterfly Count. Nature's timings are now ‘out of sync’, plants and animals are further impacted by extreme weather events, flooding, high winds and extreme temperatures. [caption id="attachment_24651" align="aligncenter" width="600"] Sloes on Blackthorn.[/caption] https://www.metoffice.gov.uk/about-us/news-and-media/media-centre/weather-and-climate-news/2025/double-record-breaker-spring-2025-is-warmest-and-sunniest-on-uk-record  

In the southern parts of Britain, beech is a dominant woodland/forest tree, further north, oak is prominent.  Beech trees are often large with smooth, silvery grey bark.  They can grow to a height of 150 feet, with a stout trunk (perhaps 10 feet in diameter) and an impressive canopy. The leaves, certainly on younger trees, may persist throughout winter in a brown and withered state — a phenomenon known as marcescence.  The root system of the beech is shallow but extensive.  The large roots spread out in all directions, and establish mycorrhizal connections, often with fungi such as Russula and Laccaria.  The mycorrhizae help the trees by supplying mineral nutrients (like phosphate) and water.  In return, the trees provide various organic nutrients to the fungus. Despite these associations, beech trees are susceptible to drought.  After the drought of the summer of 1976, many beech trees died. It is not surprising that people are concerned about the ‘health’ of beech trees in light of climate change — higher temperatures, extreme weather,  specifically periods of drought.  It was thought that climate change would reduce growth of trees like beech through the increasing frequency and intensity of summer droughts. Recently, a study conducted by researchers at the University of Liverpool looked at tree growth data (annual growth ring and masting data) accumulated over more than forty  years and found that growth was indeed reduced (by some 28%).   However, the reason was that the trees were investing more energy into reproduction than into growth.  Beech trees are known for their mast years - see previous blog on masting. In a mast year, a tree will produce enormous quantities of seeds (beech nuts✝︎). However, it seems that the changing climate is causing a ‘breakdown’ in the masting process, and whilst the trees now reproduce more more frequently.  Total seed production and seed viability is reduced.   It may be that the diminished reproductive capacity of beech trees as a result of climate change will affect their ability to regenerate woodlands and forests in the UK and indeed across Europe in the coming years.   [caption id="attachment_41997" align="aligncenter" width="675"] Marcescence[/caption] ✝︎ Masting means that so many seeds that even the most voracious squirrels cannot consume all of them * After the summer of 1976, drought damaged trees were still dying some 15 years later.

The monkey puzzle tree is a popular garden tree.  It is so-called as when first seen in this country (in the mid C19th) by Charles Austin, he is alleged to have said that “it would puzzle a monkey to climb that”.  As the tree had no common or popular name, it became the ‘monkey puzzler’ or ‘monkey puzzle tree’.  Its scientific name is Araucaria araucana, and otherwise known as the Chilean Pine or Pehuén.  It is native to the Andes of Chile and Argentina.  Not only is it a long lived tree (with a life span of a thousand plus years) but the species has been around for a long time (in excess of 200 million years).  It is sometimes described as a “living fossil”. A tree can grow to a considerable height - towards 150 feet with a trunk diameter of some five feet. Read more...

Mast is the ‘nut crop’ of the beech tree (Fagus sylvatica), but, in a broader sense, is the production of an enormous number of seeds. And the phenomenon is not restricted to beeches.It can also been seen in oaks, firs, spruces and pines.Such species are said to have ‘mast years’ and in such years it is basically impossible for animals to eat all the seeds ("predator satiation") so many seeds survive to the following spring and germinate. Read more...