There is only one living member of the genus Sequoia,   Sequoia sempervirens : the coast redwood.  It is a coniferous trees and belongs to the family Cupressaceae. The redwoods (Sequoia sp) are amongst the largest and oldest living organisms on the planet – some are possibly more than three millennia old. The trees are found along the coastal regions of California and Oregon.  Whilst the trees can live to a great age, recent studies have found that the trees are suffering as a result of beetle attack, prolonged drought and and fire damage.  Several of the long lived trees in the Sierra Nevada of California have died in recent years as a result of these ‘problems’.  It had been thought that such trees could survive fire or beetle attack Read more...

Australia has experienced some of the most dramatic effects of climate change - with the unprecedented burning of vast areas of its countryside (see previous blogs).  Recently, the weather turned to another extreme - thunderstorms, hailstorms and rain.  Large hailstones (the size of golf balls or bigger) have bombarded cities like Sydney, Melbourne and Canberra, damaging roofs, cars, trees, and infrastructure.  Flash flooding has occurred in some places due to heavy rain, plus there have been high winds and dust storms. Whilst rain has been welcomed in that it has helped to ‘damp down’ some of the fires that have been raging, the intensity of the rain is not without problems in places. Heavy rainfall can result in further damage to ecosystems. Read more...

The Earth is warming as a result of the release of carbon dioxide from fossil fuels, leading to a period of rapid and significant climate change, which is seen as an existential threat to humanity by many. It is possible that the tipping point has been reached, where the effects of global warming, such as the loss of polar ice sheets, are unstoppable.  The most dire ‘predictions’ think that cities, industries, countries, and perhaps our species will be lost. Climate change is not new and variations in the patterns of weather have provoked the collapse of regimes and cultures throughout recorded history. Social and economic constructs have unravelled and  populations have declined. Read more...

Summer 2018 saw my garden filled with colour, the sunflowers grew tall, the sweet peas colourful and scented and my ‘exotic’ red castor oil plants were almost tropical in appearance.  However, this last summer was very disappointing - many things failed to thrive or were dwarfed - not doubt in response to periods of wet and cold in the earlier months of the year.  Whilst, it is very clear that plants and animals respond to their environment and the weather that they experience, it is not clear how they respond to the long term effects of climate change.  As yet, we do not have many answers to this.  We need to understand how both plants and animals can  (1). respond or indeed adapt to changes in climate - i.e new conditions.  For example, can they change in terms of size or shape         or  Read more...

Campaigners say that we need to increase tree cover to 50% and claim it will help deal with climate change. Tree planting became a big issue in the recent general election but it's much harder than people think and probably less effective at combatting climate change than other simpler measures.   For a start it's a slow business - even in the 1960s tree-planting splurge it took a decade of feverish activity to increase tree cover by just a few percentage points.  Also you need to think carefully about where you plant and what trees you plant - the 1960's planting was mostly on uplands and with mono-cultures that were bad for biodiversity (mainly spruce and pine).  More fundamentally we need to ask what this tree-planting is trying to achieve: can the carbon fixed through one crop of trees realistically counter the burning of carbon from millions of generations of trees represented by burning coal and oil? Read more...

There is considerable debate as to the virtues or otherwise of buying a real Christmas tree over an artificial one.  This comes into focus somewhat more sharply in the post-Christmas period.   A  6 to 7 foot high natural tree (bought with no roots) would be between ten to fifteen years old and it has a fairly low carbon footprint.   As it has been growing, it has been absorbing carbon dioxide from the atmosphere and locking it away in the form of cellulose and lignin, whilst releasing oxygen.  However, this footprint changes dramatically if its fate is to be consigned to land fill.   As it decomposes, it will produce methane, a potent greenhouse gas and the carbon footprint of the tree will increase quite dramatically.   If, however, the tree is carefully composted, then its environmental impact can remain relatively low (visit the Carbon Trust for detail).   The cultivation and growth of natural Christmas trees provides a wildlife habitat, and the trees help stabilise and protect soil.  But in some parts of the world, notably Canada and the USA, the growth and supply of Christmas trees has been affected by heatwaves (as in Oregon in 2017 / 2018 - which killed many very young trees), insect damage and wildfires. The effects of climate change are particularly marked in Canada.  It may be that climate change will intensify the effect of these factors, and that Christmas tree ‘farms’ may need to move to higher elevations - where it is cooler and insect pests (e.g. balsam twig aphid) are less of a problem.  Read more...

Phenology is about observing natural events and recording when things happen.   For example, when ash or horse chestnut trees come into leaf, when the first swifts are sighted or bumblebees emerge from their nests. These timings vary from year to year. By recording such events over many years, it is possible to look for trends and see if they are associated with changes in the weather or other phenomena. Climate change has resulted in significant changes in summer and winter temperatures, and rainfall patterns.    For example,  April, May and June of 2018 were all very warm, each being at least 1.9°C above average [that is the 30 year average for 1961–90]; June was the third warmest June for the UK since 1910. Read more...

In recent times, new or different threats have emerged to upset the balance of woodland and forest ecosystems.   In the 1960’s and early 70’s concern focussed on the effects of air pollution, particularly the effects of acid rain.  This type of pollution was characterised by the deposition / assimilation of sulphur dioxide and its derivatives (sulphuric & sulphurous acid), plus various nitrogen oxides.  This air pollution was largely due to industry and traffic. Some of the most striking effects of ‘acid rain’ pollution were seen in the coniferous forests of Germany - where it was termed : Waldsterben [Wald=forest plus sterben=to die].  Read more...