Leaves have three main parts:  The petiole, a stalk-like structure that connects the blade of the leaf to the stem of the plant. Some leaves don’t have petioles,  and are known as sessile leaves. The blade or lamina, usually the largest part of the leaf.  The edge of the leaf or the leaf margin may be described as entire, toothed, or lobed. The oak leaf, for example, is clearly lobed. The blade has many veins, forming a network, carrying water and nutrients, The base, the base is the region of the blade that attaches to the petiole. A leaf is said to be simple if its blade / lamina is undivided, if the ‘teeth’ or lobes do not reach down to the main vein of the leaf.  A compound leaf has several leaflets, which join up with a single leaf stalk or petiole. When identifying tree leaves, it is always important to look for the petiole,   as a single leaflet of a compound leaf can look like a simple leaf.  More details of leaf and tree structure can be found on this link on our website. Now for a challenge.  Can you or your children find a leaf (and name the tree it came from), that Has a serrated / toothed edge Has a lobed margin Has a smooth edge / margin Is a compound, palmate leaf Is a compound, pinnate leaf Is hairy Is not green, but red or a mixture of colours Is more or less circular Is fleshy / succulent Has spines on its edges Is needle shaped Has a thick (waxy?) cuticle or is very shiny Has net venation  is marcescent (might keep you hanging around) Go forage!

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.

At some point during the months of Autumn,  the leaves have done their job (that of making sugars to be used in growth, the formation of new twigs and branches, forming fruits and seeds).  However, winter is not good for photosynthesis or growth; winds, low temperatures and low light intensities adversely affect a tree’s ability to make sugars. Indeed, if the leaves were retained throughout the winter, they might be regarded as a liability as they would use the the tree’s reserves (that were stored away in the Spring and Summer).  Plus, leaves would offer greater resistance to the wind and the tree would be more likely to suffer damage.  High winds are always more dangerous to a tree when it is in full leaf. Read more...

In early October,  BBC4 screened a 90-minute documentary capturing every aspect of life in an ancient English oak over an entire year  "Oak Tree: Nature's Greatest Survivor" focuses on a single tree in Wytham Woods, just outside Oxford, a site acquired by Oxford University in 1942 for woodland research.   The film, presented by zoologist, entomologist and broadcaster George McGavin, opens with an high-tech assessment of the tree's condition. By firing laser pulses, forestry scientists create a 3-D virtual image of the oak so they can track its size and shape over the 12 months. At the outset, in late August, it's 19 metres tall and 30 metres wide and carries an estimated 700,000 leaves. Read more...

Beech woodland is native to Southern England and Wales (roughly, south of a line drawn from The Wash to the The Severn).  However, in some parts of the country, beech has been planted systematically, for example, John Holliday of Staffordshire planted some 94000 beech in 1791.  Beech is found throughout Central and Western Europe. It is generally found on freely draining (drier) soils (chalks, limestones and light loams) such as found in the Cotswolds, Chilterns and the Downs. Read more...

Knowlands Wood at Barcombe is a hornbeam coppice with a lot of oak, both coppice and standards. When we acquired the wood some thirty years ago, it was mostly dark and relatively lifeless, having remained largely untouched since 1945.  A retired forester volunteered to start coppicing and we started to sell logs locally.   Within a year, I saw my first White Admiral. The following July my brother, who wanted to see his first also, complained that it was the commonest species of butterfly in the wood. Read more...