Skip to content

Posts tagged ‘health’

Gabriel Hemery

Latest post for The New Sylva

Securing healthy sustainably managed forests across Europe

June 14, 2011

Gabriel Hemery

Forest Europe Ministerial Conference June 2011Securing healthy, sustainably managed forests in the light of climate change and its severe consequences is one of the biggest challenges we have to solve in Europe and globally. This is the headline from the Forest Europe Ministerial Conference that opened today, hosted by Norway.

The fact that Europe’s forests are increasing represents a huge potential in helping to solve these challenges and sustain the vital values deriving from forests for people, their livelihood, our environment and future generations.

One of the main outcomes of the conference is an eagerly awaited strengthening of a strengthened policy framework for sustainable forest management throughout Europe. Ministers are expected to decide whether to enter into negotiations on a legally binding agreement on forests in Europe. The stance that the UK Government will take is currently unclear but given the UK’s exemplary record we should have high expectations.  The UK’s Forestry Commission was awarded a WWF ‘Gift to the Earth’ in 2001 for its contribution to and delivery on sustainable forestry, and was the first state forestry service to achieve 100% certification for its woods.

Gabriel Hemery

Nature’s health service

May 12, 2011

Gabriel Hemery

Green gym at woodland edge

Green exercise is any activity in the presence of nature, including woodland.  There is considerable and widespread evidence that demonstrates it leads to positive short and long-term health benefits for people; in physical wellbeing and mental health.

According to a recent scientific study 1 both men and women gain similar improvements in self-esteem after green exercise, though men showed the greatest difference for mood.  The greatest change in self-esteem was in the young and the mentally ill.  The study concluded that the outdoor environment and nature provides an important health service.

I wrote previously about an estimated 317 million people-visits per year to woodlands, a large majority of these being for dog-walking and other casual visits.   There is also increasing interest in organised exercise taking place in the outdoors.

Perhaps one of the best ideas, at least in my view, is the Green Gym run by the BTCV.  The concept is that people undertake physical work in the outdoors with the joint benefits of gaining exercise while improving the environment; for example in coppicing or clearing scrub at a local nature reserve.

A more recent phenomenon, extending the concept of organised green exercise in the outdoors, are the karate, pilates and other exercise classes springing up (excuse the pun) in city parks and other outdoor spaces.  I came across this exercise class (above photo) in a nature reserve, and it was proving a hit with the sheep flock and passing twitchers.  However, these types of activities are not without controversy.  According to The Tax Payers’ Alliance Council chiefs of two London Boroughs recently introduced new rules stating that:

.. anyone making money by being in a park should pay a fee. This means the council will now use patrols to check if anyone suspected of personal training, dog walking, nannying or even teaching for money has got the requisite license.

I’m sure it’s a personal taste but I would much prefer to don some old clothes and spend an hour or two with bowsaw or billhook, than roll around in lycra while watched by sheep.  What do ewe think?

Gabriel Hemery


1 Barton, J. and Pretty, J. (2010).  What is the best dose of nature and green exercise for improving mental health? A multi-study analysis.  Environmental Science & Technology, 44 , (10),  pp. 3947–3955.  DOI 10.1021/es903183r.  Read Abstract

A looming threat to tree and man

May 4, 2011

Gabriel Hemery

The Oak Processionary Moth is a serious pest, not only for oak trees but also for human health.

The oak processionary moth

The oak processionary moth (OPM) Thaumetopoea processionea gets its common name from its habit of moving along oak (it’s food plant) in processionary columns.  It is a species native to southern Europe, which spread northwards during the late 20th Century, being recorded first in the Netherlands in 1991, and then Belgium, France and Germany soon afterwards.

Colonies of the OPM in the UK were first discovered in 2006, in a housing estate in the London Borough of Richmond. It was identified after a large number of local people reported skin rashes. It is apparent that the OPM had arrived on imported Cypress oak (Quercus robur f. fastigiata) trees.  Colonies were sighted later at Brent, Ealing, Hounslow and Richmond Upon Thames, including Royal Botanic Gardens Kew.  The OPM colonises urban areas readily, preferring warm, sunny and sheltered sites for breeding.  In 2010 a new infestation was spotted west of London, at Pangbourne in Berkshire (source).  It is likely that milder winters and fewer Spring frosts may be contributing to population expansion (read more about trees pests, climate change and global trade).

Significant resources have been expended in attempts to control OPM.  In 2011, Richmond Park alone will be spending £50,000 in attempting to control it (source).  Initial confidence that the first colonies across London could be contained has given way to real fear that OPM may now be out of control:

“The area affected by OPM is growing steadily. It seems possible that attempts to eradicate the pest may fail  …  despite the hard work and effort put in by many organisations and individuals, we may be on the brink of failure.”
London Tree Officers Association website (accessed 3rd May 2011)

Effects of OPM on oak trees

Oak processionary moth nest

Nest of oak processionary moths (Thaumetopoea processionea) on an oak stem. Photo Falko Seyffarth (Wikipedia)

Oak trees colonised by OPM can be seriously defoliated and there are reports of tree death in some instances.  However, the trees will normally recover and leaf the following year. On the European continent OPM has also been reported on beech, silver birch, hazel, hornbeam, and sweet chestnut but normally only when neighbouring infested oak trees.  Oak trees under 2m in height are not normally colonised.

Human health

The caterpillars of the third to sixth instars have poisonous hairs or setae that carry a toxin that can cause serious irritation to the skin, eyes, nose and throat of humans and other animals.  If inhaled they can cause respiratory distress, asthma and even anaphylactic shock.  Read more.

Not only should the caterpillars never be touched but even being in proximity to them can be dangerous as their hairs can be carried in the wind.


oak processionary moth health warningYou should never attempt to handle the caterpillars or disturb their nests.

If you suspect an incidence of oak processionary moth, sightings can be reported to Forest Research by telephoning 01420 22255 or by e-mail to

Gabriel Hemery

Read more

Being positive about street trees

April 20, 2011

Gabriel Hemery

street tree slaughteredTrees in our streets improve air quality, provide beneficial micro-climate, enhance property values and aesthetics, attenuate storm water, conserve energy, reduce noise pollution, provide wildlife habitat, and have a positive effect on physical and mental human health.

There’s no denying that trees can cause problems in the built environment. Their roots can disturb pavements, roads or underground services, they can be too close to buildings undermining foundations or blocking sunlight and views.  Fallen trees or limbs in storm events can block roads and railway lines, they sometimes damage property and do sometimes kill people.  Perhaps it’s no wonder that trees are increasingly seen as a liability.

Street trees should be managed for their benefits however, as well as for risk and hazard.  I’m often horrified at the sight of a street tree, stripped of its limbs and decency – all in the interests of health and safety.  There is a cultural obsession in our towns and cities in trying to remove as much risk as possible but this can be detrimental to tree health.   This is important because poor health is linked to tree stress and in turn its susceptibility to tree pathogens; and we know that threats from tree pests and diseases are ever-increasing.  Furthermore, a decline in tree health will more likely lead to a tree that it is prone to shedding limbs or uprooting: over-pruning a tree is likely to be worse than not pruning at all.

The larger the tree, the greater the benefits.  We need more large trees in our streets, and for these to be lightly maintained for both their and our benefit.  Urban foresters and town planners will need to challenge perceived wisdom in tree management, as we aim to make our towns and cities fit for the 21st Century.   Ultimately, we need to start looking at the entire street tree resource in any town or city as an Urban Forest, and plan to deliver all the benefits listed above.

Be aware of Ticks and Lyme disease

April 4, 2011

Gabriel Hemery

Tick bite prevention week websiteI have a friend who was lucky to have spent their childhood roaming the New Forest.  Less fortunately, a disease lay deep within her bloodstream for decades: the result of being bitten by a tick infected with Lyme disease while she explored the forest as a child.  The disease was only recently diagnosed, after she underwent multiple tests for symptoms that for some time made her suspect multiple sclerosis.

Her experience resonated deeply with me.  I spent my youth on Dartmoor when the removal of several dozen feeding ticks off my body at bath time was a common, often daily, chore.

Everyone who spends time in the outdoors should be aware of Lyme disease, and with the coming of Spring, now’s a good time to become TICK-AWARE.  Next week is also National Tick Bite Prevention week.

What is a tick?

A tick is an external parasite that feeds on the blood of mammals and birds.  In the UK there are two families of ticks, hard ticks and soft ticks, and it is usually hard ticks that spread Lyme disease:

  1. The most common ticks to transmit Lyme disease are Ixodes ricinus (also known as the sheep tick, deer tick, wood tick, and castor bean tick)
  2. Ixodes hexagonus (the hedgehog tick)

What is Lyme disease?

Lyme disease, or Lyme borreliosis, is an infectious disease caused by the bacterium Borrelia burgdorferi that can be carried by a tick, and which can be transfered to humans by a tick bite.  The disease is classified by the World Health Organisation as an infectious or parasitic disease.  The name ‘Lyme’ comes from a town of the same name in Connecticut where US researchers first identified the disease, although in Europe it has been known by various other names for centuries.

When infected by the disease it may take anything from two to 32 days for symptoms to show.  Early symptoms include feeling generally unwell or flu-like, headache, muscular aches or pain, stiff neck, joint pain, tender glands and sensitivity to temperature, sound and light.  Sometimes a characteristically-shaped and expanding ‘bull’s eye’ skin rash may  appear, which is termed Erythema migrans or ‘EM rash’.

If left untreated patients can develop a range of symptoms termed ‘late-stage’ or ‘Chronic Lyme disease’, which can include my friend’s MS-type symptoms, plus arthritis, sleep disturbance, cognitive difficulties or chronic fatigue syndrome-like symptoms.

When are ticks active in the UK?

Ticks are generally more active between March and June. There is another peak in activity between August and October.  During the winter, ticks are normally less active.  Be aware when travelling abroad as the climate will affect tick the timing of activity, while there may also be different tick species present too.

Prevention of ticks

After hatching a larval tick will seek a host (‘questing’), where it waits in ambush on low vegetation with its forelegs outstretched.  A tick can sense chemicals, heat and movement from a passing host.  As a host brushes by, the tick will latch on using hooks on its forelegs.  Once on the host it searches for a suitable feeding site.  Be warned: ticks like the warmest parts of your body, check especially around your ankles, behind the knees, under the armpits and around your groin, although they can start feeding anywhere.

Preventing ticks can be difficult.  Being aware of the potential is an important first step.  During certain times of year (see above) you would be wise to think twice about entering dense ground vegetation especially, in my experience, bracken and tall grasses/sedges/rushes.  Long clothes that cover exposed skin, especially legs, may be a good idea in practice but not always practical during summer heat.  You could try tucking your trousers into your socks too.  Smooth rather than coarse or wooly fabrics may be better at repelling ticks.  Pale colours will show up crawling ticks en route to some warm part of your body.  Some insect repellents also claim to be effective in reducing tick infestation including Mosi-guard and Deet.

What to do if you find a feeding tick

You should remove a feeding tick as soon as you can although when first attached (i.e. before swollen) a nymph they can be hard to spot.  Get into a routine after being outside to check yourself.  Make sure you remove a tick carefully as it is possible to leave its head behind in your skin, where it can lead to infection.  I recommend that you visit some of the links below, some of which include step by step practical guidance with illustrations, on how to remove a tick.

Gabriel Hemery

Find out more

%d bloggers like this: