Cracks in horizontal branches - hazard beams?

An absolutely fascinating sight on a long near-horizontal branch on a beech tree.





Commonly found in Beech and Oak, according to Arbtalk. "This fault tends to happen to phototropic limbs (extending rapidly toward light) 90% of the time they are growing on the North side if in open ground as the limb tries to reach away from the main body of the crown to reach out from canopy shading.

it is very common, and in most cases removal of the branch is not needed, simply reduction by one third the length is usually enough to manage the hazard. This is a good way of maintaining the habitat that is the hazard beam. In time they stabilise and occlude, how many limbs have you ever cut only to see they have a large crack at their centres? Removal makes a large wound at the stem junction, a higher future risk than a stabilised hazard beam fracture.

Dog legs where a leading tip has died and a sub order shoot takes over as in this case are more prone to the fault, and worth looking out for when managing trees, especialy in parkland or open grown situations.

Also worth noting that Matthecks slenderness ratio can be applied to limb assesment as well as stem calculations."

South East Bat Conference

Bat Conference in Chatham

A fantastic bat conference today, full of information relevant to trees and tree wardening. One of the very interesting presentations was from the Kent Bat Group including their new project on bat boxes in woodland, focussed on the Blean woodlands in East Kent.  This has developed out of work with the North Bucks Bat Group, who have researched ideas on the siting, types, etc. of bat boxes, and who have partnered KBG in this new work. It is clear that boxes on trees don't have to be in the sunniest spots - this may suit some species such as pipistrelles perhaps, but for some woodland specialists such as Bechstein's and Brown Long-eared Bats, deep shade is an excellent spot to place a box in woodland! Even where there are large numbers of boxes in a wood, bat populations may still spend about 80% of their nights roosting in the trees rather than the boxes - showing how important older trees suitable for bat roosts are!

It is early days but the first use of a box by a bat in Kent has already been recorded. This is a photo from the Bedfordshire Bat Group blog section of their October Bat Box checking. Sometimes the boxes are higher in the trees, which certainly wouldn't suit me! However I would love to put some bat boxes up in Hadlow - if only I could afford the Schwegler boxes which last long enough to be worthwhile, and if I could get a roost visitor license to allow me to check the boxes!

Bats must use many of the trees in and around Hadlow as roosts, and in consequence there should be controls on tree surgery to likely trees - there doesn't seem to be much evidence for these controls being in place over tree work in many areas - but nuff said I think.


A tree forms an essential part of an often complex ecosystem that provides a variety of habitats for
a range of different wildlife species, including bats. Of the seventeen bat species breeding in the UK, fourteen are known to roost in trees. Some bat species rely exclusively on trees for roost sites, whilst others use them for part of the year. All seventeen species forage in woodland and along woodland edges.

Any tree can be used as a bat roost, as long as it provides shelter, e.g. in the form of splits, cracks,
holes and cavities in the trunk and branches, loose bark and ivy cover (Figure 1). Roosts can be at
any height in the tree, although upper trunk and branches are probably more common.

September - Hazel

Interesting shot of a hazel bud in the axil of a leaf - and intriguing to see the colours of the minute hairs on the stem and the petiole:

This shows the coarse hairs you do get on hazel shoots, and apparently petioles:

August - Field Maple

Pimple galls, caused by an Eriophyid mite

June - English Elm

This English Elm leaf on the access trail looks as though it has developed tiny bristles on its upper surface:

May - Alder

Young female flowers.

May - English Elm

If you ignore the hoverfly resting on it, this is a fairly normal leaf of the English Elm, Ulmus procera, showing the double toothing along the margin serrations, asymmetric leaf shape, and apparently slightly shiny, if deceptive, upper surface of the leaf.

April - Elm

The leaves are small and rounded, with rough upper surfaces, so this should be the English Elm, Ulmus procera, the commonest clone in England. The blobs on the upper leaf surfaces are caused by the Eriophyid mite, Aceria ulmicola, (Nalepa) (=Aculus = Eriophyes ulmi = campestricola) which is supposed to only infest English Elm, according to some but not all authorities.

As with most elms, the stems are often heavily winged with corky outgrowths:

The suckering trees on the access trail are repeatedly attacked by the bark beetle and continually re-infected with the Dutch Elm Disease fungus, causing them to die-back again and again.