Mosses and lichens are often overlooked as part of the woodland flora.  The same is true in towns and cities.  They can be found on the trunks of trees, on walls and rooftops.  They are epiphytes, that is,  plants which grow on the surface of another plant. They derive moisture and nutrients from the air, rain, and debris that is deposited on and around them. They cling to these surfaces, come rain or shine.  Climate change and pollution affects these small, often unnoticed plants in both woodland and urban settings.    As global temperatures continue to rise, many places face extremes of temperature.   Heat waves are becoming more common, as we have recently experienced.  Some 1500+ heat-associated deaths were recorded in England during the heat waves of  last summer [2025].    The highest rates were among elderly individuals [aged 85+] with the impacts felt particularly in care homes and hospitals.   London and the East of England recorded the highest number of heat-associated fatalities. Cities and urban environments often face the brunt of these climate extremes.  The concrete, brick and tarmac of cities absorb and hold onto the sun’s energy creating ‘urban heat islands’. Urban temperatures are often several degrees higher than surrounding rural areas. Urban temperatures have soared in recent times, for example in New Delhi, a record high of 126.1oF (52.3oC) was recorded. Such temperatures claim lives. This year parts of Europe have recorded temperatures of 40oC. Urban trees suffer in this heat as do their epiphytic flora.  The mosses and lichens in our cities fall into this category.  Researchers at Leiden University have investigated the effect of changing temperatures on the mosses and lichens growing on Lime (Linden) trees in Dutch cities (Amsterdam, Leiden, and Rotterdam).  They sampled numerous sites, measuring the microclimate for each tree and recording the species present.  They found, perhaps unsurprisingly, that urban heat islands were reshaping the moss and lichen communities.  Species that were adapted to drier, brighter and nitrogen-rich environments were favoured; for example, a type of wreath lichen [Phaeophyscia orbicularis]. When wetted this turns from a grey / brown colour to green, and its symbiotic green algae can begin to photosynthesise producing sugars. Those species that were associated with moister and shady conditions were found to be ‘losing out’.  They noted that the larger lime trees supported more diverse epiphyte communities; this might be associated with the older bark offering more micro-habitats for the mosses and lichens to ‘gain a foothold’.   [caption id="attachment_41261" align="aligncenter" width="675"] Lichens on an old stone wall.[/caption] The changing climate and urban heat islands are altering the species that can survive in our towns and cities, on trees and artificial surfaces.

As we move through Autumn,  the leaves of deciduous trees have ‘done their job’.  Their capacity for photosynthesis dwindles (as does the light and temperature.  In fact, the leaves become a ‘liability’ to a tree, in that they would make use of the reserves that have been stored away. Also, the leaves offer resistance to the winds of winter so a tree is likely to sustain damage. If branches are lost from the stem,  then bacteria and / or fungi could enter.  The leaves are ‘discarded’ as Autumn progresses.  The green colour of the chlorophyll is lost and other colours emerge - reds, oranges and yellows. These colours are associated with different pigments, the carotenes, xanthophylls and the anthocyanins.   As the leaves are lost so the trunk and branches becomes more apparent, but they are not necessarily ‘naked’ - devoid of cover.  Indeed, walking through a woodland at this time of year, one is often struck by the abundance of mosses. Tree trunks are often laden with ‘carpets’ of moss and their branches bear ‘decorations’ of many different mosses.  Beneath the tree, there is often a soft, spongey layer of mosses. Mosses are bryophytes.  They are ‘simple’, non-vascular plants ; that is to say they do not have sophisticated transporting tissues (of phloem and xylem).  Nor do they have true roots, instead they have structures called rhizoids (which may be uni or multicellular). They live in moist places, indeed they are dependent on water for their reproduction. Mosses or rather their ancestors were some of the first plants to colonise land (which was the rather inhospitable rock of the Ordovician period), previously there were only algae in the seas.  Mosses develop sex organs, The male organ is called is called an antheridium, it produces male gametes that can move by means of a flagellum.  These gametes swim in a film of water towards the female organ (an archegonium).  When the male and female gamete fuse, the structure grows to form a sporophyte.  This eventually produces a capsule, which releases spores that grow on to form a new generation.   Mosses seldom grow to any great height, mainly due to the absence of supporting mechanical tissue but they can form extensive mats in damp, shady places (as can liverworts).  These mossy mats can in some situations prevent soil erosion, and in others allow the accumulation of humus and soil enrichment / formation.  An extreme example of the accumulation of mossy material I can be seen in the case of the moss Sphagnum.  Sphagnum is unusual in that can hold many times its own weight in water; because of this absorbency, Sphagnum was used as a wound dressing in WW1. It grows in acidic, marshy conditions, often forming a sphagnum bog. The low fertility and cool climate result in slow growth of the Sphagnum (and other plants). The decay of dead plant material is even slower (due low oxygen levels). Hence, peat forms and accumulates.  Large areas of the land can be covered to a depth of several metres with peat.  Peat bogs are a very effective means of carbon sequestration, locking away carbon for hundreds iff not thousands of years.  Unfortunately, many have been drained and allowed to dry out  and / or the peat cut from them as a form of fuel.  When peat areas are drained (channels are cut through the peat), they degrade and dry out.  Then, they are then at risk of burning as has been seem in recent years -for example, in the U.K (Saddleworth Moor). [caption id="attachment_39795" align="aligncenter" width="675"] Moss (Dicranum?) growing with Lichen (Cladonia sp)[/caption] 'Mossy ball', 'autumn leaves ', moss and lichen photos - thanks to Art Symons.

Following seemingly weeks of awful weather and awful news the 16th March was an amazing spring day, clear blue skies and gentle warm sunshine - a good day to see what was new at the wood.  As it turned out there was plenty. We heard our first Chiffchaff of the year, and saw Great Tits beginning to explore nest boxes. When we arrived the pair of Buzzards were active, and we also noticed a male Wren busy building a nest in a large insect box we were given at Christmas, and fixed close to the ground by our coffee spot. They are confident birds, but difficult to photograph because of their cryptic colouring and speed, and their penchant for the dapple of undergrowth and nooks and crannies. However this bird was out and about, and back and forth to the box collecting moss from the base of near by trees.  Read more...

Last year, the Woodland’s blog reported on the moorland fires around the U.K. and this Easter weekend yet another fire has been reported at Ilkley  These fires have a devastating effect on local wildlife.  Sadly,  extensive peat wildfires have occurred in places as diverse as Indonesia (in 2015) and Greenland.   The fire (in Indonesia) and its associated smoke was responsible for the deaths of people and animals,  and caused billions of pounds of damage through the destruction of homes and businesses.  Also,  the fires released truly massive amounts of carbon dioxide (a greenhouse gas) into the atmosphere. Read more...

Yew woodland (in Southern England) tends to develop on the thin soils that form over chalk, often on the sides of dry valleys . They can be found along the North Downs, and in West Sussex on parts of the South Downs. Yew woodlands can also be found in the Cotswolds and in the Wye Valley (on limestone). In Ireland, there is a significant Yew wood near Killarney, again growing on top of limestone. Yew woodland may develop from chalk grassland, when grazing by sheep or rabbits is removed. With no grazing, Juniper and / or Hawthorn start to grow.  Then, between these, shade-tolerant Yew seedlings begin to grow.   Eventually, the Yew will overtake the Juniper / Hawthorn, and shade them out. The dead remains of juniper and hawthorn sometimes may be seen on the floor of a Yew woodland. Read more...

The North Wales Wildlife Trust has reserves where it is trying to involve the public but also wants to encourage long-eared owls to breed. Surprisingly, perhaps, long-eared owls do not build their own nests and there are only about 2,000 pairs, usually adopting unused nests of other species. These owls are threatened by the growing population of buzzards and corvids, so Jonny Hulson and his colleagues from NWWT are working to encourage the owls to nest, by getting the public to build nests with wire, twigs and moss, as shown in the picture below.  Jonny hopes that the nests will also be used by hobbys and merlins. Read more...