ESSEX   BOTANY   AND   MYCOLOGY  GROUPS 

'BLACK' POPLARS IN THE U.K.

Identifying, finding, locating, sampling for DNA analysis, preserving, cloning with truncheons, and the potential for localised historical tracking of Water Poplar propagation.

 Ken Adams

What is a Water Poplar?

It is the old English name for what we now call the ‘Native’ Black Poplar or the ‘Atlantic race of the European Black Poplar’: Populus nigra betulifolia. Neither vernacular is particularly appropriate as it would seem that many if not all our trees are probably no more native than the ‘English’ Elm; now known to have been introduced to England in the first century AD and to derive from an Italian clone to the east of Rome, - given the less embarrassing appellation Atinian Elm; or the various other named variants of Ulmus minor which have such genetic uniformity that they too must have been selected from a continental continuum and propagated over here by man. Furthermore, Populus nigra extends right across Europe into central Asia and south into N. Africa, so it’s hardly appropriate to call P. nigra sensu lato the ‘European’ Black Poplar. Hence my endeavour to promote the old English name to minimise confusion with so-called ‘Italian’ Black Poplars/Hybrid Black Poplars and other Euroamerican and Euroasian hybrids and the various American Cottonwoods’.

Why are Poplar species in trouble all over the world?

Because of the high viability of hybrids between poplar species the genetic integrity of many the wild species is being infiltrated by genes introduced by hybrid pollens. Water Poplars are endangered not so much because of their relatively limited numbers but because they are unable to reproduce by seed in the U.K. Unless we clone them vegetatively, or artificially pollinate female catkins in sealed bags, followed by growing up the seedlings in an artificial habitat to prevent contamination from hybrid pollen, - they are as doomed as our commercial Turkey population would be without artificial insemination. Furthermore, the same situation is now arising in North America, where our P. nigra together with several Asian species have been crossed with their native taxa and planted in large numbers, and are now shedding contaminating pollen, thus endangering their genetic integrity and ability to reproduce by seed.

In fact the native species of the genus Populus are being endangered world wide by the huge numbers of multiple crossings taking place as mankind endeavours to create trees that are faster growing, have denser grained wood or longer fibres, or are drought resistant, or disease free etc. by swapping their highly inter-compatible genomes around. Even the Aspen, Populus tremula has been crossed with the American P. tremuloides, the hydrid now being widely grown in Sweden for timber and fibreboard. Virtually all the European countries are now engaged in crossing poplar species and clones to develop new types of trees that will either grow under short days or at high altitudes (Sweden and Switzerland), or in dry soils, or for particular purposes e.g. paper pulp (selected for fibre length), plywood or veneer (Italy and France in particular). Genetic engineering has also been used to remove pigments that otherwise affect paper production. Other hybrids/clones are being developed for ‘passive remediation’ a euphemism for the removal of toxic waste substances in soils by uptake via their roots. In the case of difficult hybrids they circumvent cross-compatibility inhibitors in the seed by resorting to embryo culture, extracting the hybrid embryos soon after pollination and growing them on nutrient agar. To bulk up they largely propagate the female forms, and do so not by taking cuttings, but by grafting buds or green shoots onto stocks of other forms. Thus any suckers will probably be different genetically! At the present time, of the vast numbers of Poplars being planted for commercial or ornamental purposes all over the world, some 90% are estimated to be hybrids involving only five species, and a relatively small number of clones. Although many of the world’s Poplar species are intercompatible and do cross occasionally in the wild they do not intergress to any great extent. Hybrid pollen being genetically intermediate, is however, highly successful at pollinating a wide range of native species.

Our U.K. trees are all said to belong to a doubtfully distinct form separated off as var. or subsp. betulifolia. Although samples were collected for herbaria now in the BM as long ago as the 1600s, nobody seems to have noticed any difference between our trees and some of those elsewhere in Europe, until they were described by Francois Michaux who found it growing on the banks of the Hudson river near Albany New York, and as large trees in New York City (1803), and thought it probably native to somewhere in the USA. It was subsequently propagated and sold by a firm in Rochester NY under the name of P. elegans. It is now suspected that it was actually introduced from Europe some time in the 1700s. Even in Flora Europeae Edition One 1964, Flora of the British Isles 3rd revised edition1989, and Oliver Rackham’s various books, there is no mention of varieties other than the Lombardy Poplar. Widespread awareness of the existence of var. betulifolia as a distinct form seems to be very recent and to coincide with the growing desire to label taxa as ‘rare and endangered’ – much more justifiable if it’s not lumped in with a tree found right across Europe to central Asia, and in N. Africa.

If we are not careful, the assumption that that all our ‘wild’ U.K. P. nigra material belongs to this form, which has been given a closely stereotyped circumscription, -will preclude recognition of other forms of P. nigra that may occur in the U.K. Throughout its Eurasian range P. nigra seems to be more or less continuously variable morphologically, except where, as in the elms, clones have been propagated to form genetically uniform populations. Unfortunately it is difficult to fully comprehend the extent of the variation and the distribution of variants, as these are seldom described in sufficient detail, and variants have been bulk cloned and moved around Europe, but from my observations it seems likely that forms other than ‘typical’ betulifolia do occur in the UK.

In ‘typical’ betulifolia the laminas of the leaves and first soft shoots are pubescent when young, as are the petioles, which have more persistent hairs. The degree of hairiness of the petioles in U.K. clones is however very variable. Some are villous to the naked eye, others have tiny 0.5mm hairs only to be seen with a x20 lens, and some have no hairs at all – the hairs tend to snap off by late summer anyway. The axes of both the male and female catkins are also ‘typically’ hairy, - but here again forms have been described from the U.K. that have glabrous catkin axes combined with hairy petioles, as long ago as Elwes & Henry 1913..

As one moves south and east on the continent into drier climates the degree of hairiness of the leaves, petioles and first year twigs apparently increases, presumably as a xerophytic adaptation to stabilise the shearing layer, and another variety var. caudina Ten. (= var. pubescens Parl) Woolly Black Poplar - has thus been recognised. Whereas betulifolia occurs primarily in Britain, the low countries, and France from Normandy south to the Pyrenees; caudina occurs in Spain, North Africa, central and Southern Italy, the Balkans and Iran. The closely related var. afghanica (= thevestina) regarded by some as a separate species, and by others as a cultivar, has a smooth white bark and pyramidal habit, and occurs in south-west Asia.  [None of these forms however have the ciliate laminal margins of the American P. deltoides]. As one progresses south the degree of variation of P. nigra increases, and is reflected in the number of clones, which are around ten times the number south of the Pyrenees, in Italy and the Balkans, as in the north of Europe, the latter apparently having been recolonized after the last ice age by a small selection of clones from these presumed glacial refugia after they had struggled across the barriers of the Pyrenees and the Alps.

At the other extreme, the so-called var. typica or P. nigra var. nigra is completely glabrous. It is found in central and eastern Europe, and is said to be occasionally ‘planted’ in the U.K as opposed to occurring in the ‘wild’. The big question that arises however, is are we simply talking about relative degrees of hairiness, or are there other characters which separate var. betulifolia and var. typica ? If not then we are making a mountain out of a molehill?

Elwes and Henry in 1913 made an attempt to characterise betulifolia and typica. They say that the leaves of the two are identical, apart from the pubescence of the former, and the buds are greenish tinged with brown in the former and reddish in the latter, the twigs orange-yellow by the second year in the former and ash grey in the latter. They also mention, as many of us have found, that the degree of burring is very variable, as is the occurrence of epicormic shoots, - and I wonder if this could perhaps be caused by a widespread virus or phytoplasmid infection that man has selectively propagated in the majority of our U.K. material.

So where have we progressed to so far? At this stage I would claim that we have probably been overlooking some perfectly good P. nigra in the U.K. because individual trees are either not significantly burred or do not have hairy petioles. Furthermore, from their DNA, some of my veteran trees are coming out as ‘good’ P. deltoides-free P. nigra despite not having particularly noticeably down-swept branches or up-swept tips, or significant burring.

Fastigiate (tall and spindly) P. nigra clones.

Before discussing how to distinguish P. nigra in the field from the numerous hybrids involving hybridization at the specific level, we need to consider some of the widespread cultivars and hybrids within the P. nigra complex. The commonest is P. nigra ‘Italica’ (formerly called var. italica). [The modern convention is to enclose cultivar names in inverted commas and give them a capital first letter and regular as opposed to italic type]. This is probably a single gene mutant of P. nigra typica which has a dominant apical shoot and steeply ascending branches forming a narrow spire-like tree, the so-called ‘fastigiate habit’. It is a male clone that has been propagated by cuttings all over the world as an ornamental tree and wind break. It has a short life growing to full height in about 15 years. Because it is otherwise a typical P. nigra it has all the other characteristics of P. nigra, including insect parasites and diseases. Because typica is glabrous it too is glabrous. However there are complications. It has been crossed with P. nigra betulifolia to produce a whole family of  male only cultivars ‘Plantierensis’ – these are less spindly, have a heavy tapering trunk at the base, and are better adapted to the cool humid climate of northern Europe - but because betulifolia is involved they are hairy! Why mention it? Well they are now more commonly planted in the U.K. than ‘Italica’. Furthermore there are female fastigiated clones of P. nigra. One of these, quite commonly grown in the UK, is broader than ‘Italica’ and and resembles ‘Plantierensis’ – it’s called ‘Gigantea’. There are several additional female fastigiate clones that have been selected and widely planted in France and around the Mediterranean and will probably appear over here. Yet another P. nigra variety with a columnar habit is var. thevestina. This originated in central Asia but is now widely planted in southern Italy, N. Africa, western Asia and the Near East. It has a smooth grey/white bark. One of its cultivars: ‘Hamoui’ from Syria, is widely used for carpentry. So if you are a BSBI Vc recorder beware of trying to name fastigiate hybrid poplars – there are dozens of cultivars around – and the number is growing!

Why mention all these fastigiates? Several reasons. Firstly, it can be difficult to separate very young typica or betulifolia from one of the young fastigiates and secondly if one of the fastigiates has been coppiced it may have developed a broad habit. Thirdly, you will now appreciate that finding a young tree with hairy petioles is no guarantee that it is betulifolia. Fourthly, although these fastigiated Poplars are all 99.9%+ P. nigra in origin they are so abundant that they are likely to genetically contaminate any seed produced by our betulifolia with the fastigiate habit. Finally if you are recording fastigiate poplars for a local flora – beware – a superficially similar ornamental fastigiate mutant of Quercus robur is all the rage with local authorities at the present time. A close look will reveal typical Q. robur leaves.

EuroAmerican/Asian Hybrids.

As a conservative estimate there are at least 30 recognized taxa of the genus Populus worldwide worthy of specific rank (OECD 2008). These estimates apparently largely ignore the monumental tome, the ongoing web based multinational-authored Flora of China, in which are described and illustrated 73 species, and nine hybrids – as well as many varieties. Of these 43 species are additional to the 30 on the previously recognized list giving us around 73 species. This is in contrast to just 14 species in the whole of N. America. It would seem therefore that China is probably the centre of speciation of the modern genus, although Populus as a genus is believed to have its origins in the Paleocene of tropical N. America. The southernmost naturally distributed species appears to be the Kenyan endemic P. ilicifolia. If you are confused already, the bewildering range of hybrids involving up to five generations of crossing/back crossing will further confuse. Many of them are naturally interfertile, and of those that are not mankind is doing his best to cross artificially! Not only have many of the species been further selected for ‘promising’ cultivar clones, numerous further clones have been and are still being selected from complex hybrid crosses.

The genus has been divided up into 5-6 subgenera of which the Tacamahaca (Balsam Poplars) and the Aigeiros (Cottonwoods and Black Poplars) cause us most concern in the U.K. These are all cross-compatible, and very closely related. Confusingly, if you put betulifolia shoots in a polythene bag for a few hours, or stand down-breeze of a freshly leafing tree in spring, you will detect a strong balsam smell that emanates from the sticky buds – despite the use of this as a character for separating the two groups in Stace II. In the wild all of these two groups are essentially riparian species characteristic of river flood plains, but they are poor competitors, and require open weed free conditions for seedling establishment.

The hybrid P. nigra x P. deltoides (P. x canadensis) or (P. x euramericana) confusingly called Italian Black Poplar (because the first cross arose in Italy) or Hybrid Black Poplar (even more ambiguous) has now been cloned in numerous forms, all faster growing than P. nigra and now planted in their tens of thousands in the U.K.  Curiously the potential cross P.nigra female x P. deltoides male is incompatible, and only works the other way round. In Table One I have expanded  the ancestry of some of the commoner hybrid cultivars grown in the U.K. covered in Stace II to give some idea of the complexity:

TABLE ONE:

M    ‘Serotina’         nigra typica [m] x deltoides [f]

F     ‘Marilandica’   nigra typica x deltoides x nigra typica

F     ‘Regenerata’    nigra typica x deltoides x nigra typica x nigra typica x deltoides

M    ‘Eugenii’          nigra typica x deltoides x nigra typica x nigra typica x deltoides x‘Italica’

All these have the common characteristic that they are glabrous, giving us one way of separating them from betulifolia. Just to complicate matters, however, a cross between betulifolia and deltoides – [and therefore pubescent] has recently been re-introduced into the UK from America. Furthermore, although ‘Serotina’, ‘Marilandica’ and ‘Regenerata’ are largely used in amenity/ornamental plantings, a further hybrid ‘Robusta’ with a tall straight trunk is planted in rectangular arrays in damp ‘Cricket-bat Willow-like plantations’ for timber, and in long rows as screens or wind breaks, and is probably the most abundant form in south-east England. Because it has betulifolia as one of its ancestors it is pubescent. Eugenii is also grown in plantations and also has the habit of a Cricket-bat Willow, but it is glabrous.

M    ‘Robusta’        deltoides ‘Cordata’ x nigra betulifolia x ‘Italica’

All the Poplars have a base number of chromosomes of n=19, and most of them are diploid with 2n=38, and this applies to the hybrids involving nigra and deltoides.

Characteristics of P. nigra versus P. x canadensis [=euroamericana]

Maiden P. nigra trees that have been allowed to grow for 60 years or more are now extremely rare, most trees are either low, middle or high pollards. Many modern plantings are ridiculously crowded, in avenues or tightly packed groups. For these reasons it is virtually impossible to discern from the form of the tree whether you have a betulifolia/typica. Quite often one of the fastigiates has at some time been coppiced and it then becomes very difficult to separate them from betulifolia.

I have listed some characteristics separating the commoner deltoides/nigra hybrids from nigra typica/betulfolia:

Populus x canadensis (Populus nigra typica x deltoides) ‘Italian’ Black Poplar

Leaves with cartilaginous margins, thin, lamina not leathery, light green, rather large, teeth rounded, hooked and curving forwards towards the apex, base truncate to cordate, two glands at junction of petiole and lamina, petiole and leaf veins glabrous. Terminal shoot leaves similar to the others. Buds and young shoots not smelling of balsam. Trunk and branches without burring or bosses. Branches ascending, not downward arching. Bark deeply fissured with rounded spaghetti-like segments, usually grey in colour. Commonly supports Mistletoe. Never supports the aphids Pemphigus spyrothecae, P. bursarius, P. populi or P. populinigrae agg.

Cultivars: 

‘Serotina’ male.               ‘Marilandica’ (P. nigra typica [=nigra] x P. x canadensis ‘serotina’) female

Populus nigra betulifolia/typica Water Poplar, ‘European’ Black Poplar, ‘Native’ Black Poplar.

Leaves without catilagenous margins, lamina rather thick and leathery, deep green, margin sinuous around most of circumference, may have slightly hooked teeth towards the base. Base of mature leaves cuneate to truncate but never cordate. No glands at junction of petiole and lamina initially but may be one later on, petiole and main veins below softly hairy in spring in betulifolia. Terminal shoot leaves markedly diamond shaped with cuneate base and long pointed apex. Further back, leaves may be truncate but not cordate. Buds and young shoots smelling of balsam. Trunk and branches usually, but not always, burred and bossed with epicormic shoots. Trunk black, fissured with slit-like fissures as if cut by a knife and pulled apart. Upper branches may however have grey spaghetti-like bark in large mature trees. Main branches arching over in wide arcs, often touching the ground. N.B. in recently pollarded trees these may be steeply ascending for the first 5-6 years. Rarely if ever supports Mistletoe [2 records]. The aphids Pemphigus spyrothecae, P. bursarius or P. populinigrae agg. all specific to P. nigra (including P. nigra typica, P. nigra ‘Italica’ (Lombardy), P. nigra betulifolia and P.  'Plantierensis'.

Populus ‘Robusta’ (P. nigra betulifolia x P.nigra italica x P. deltoides) male.

Given these possibilities, how do we go about separating P. nigra in the field from first generation hybrid black poplars and possible second generation back-crosses?

First of all I should mention that there are a lot of red herrings in the literature. Supplimentary characters such as bronzing of young leaves or red pigmented petioles, for example seem to be reactions to a high U.V. flux. Since P. nigra usually leafs up before the hybrids in the spring, it may not exhibit either characteristic, whereas the latter leafing up later on when the UV flux is higher usually do. However, if we have fine sunny weather in April/May P. nigra can be just as bronzed or red-petioled, though they may not be the following year.

They all have red male catkins, but those of ‘Robusta’ emerge first and are dark red, betulifolia male catkins emerge next, and are of such a bright red colour that the whole tree can be seen glowing red for a mile or so away. Next come the other various hybrids, mostly of a darker less conspicuous red, not so readily picked out from a distance. [N.B. male catkins drop soon after anthesis but their shrivelled remains can also usually be found in the leaf litter or grass under a tree well into August. Similarly, the remains of the female husks and fragments of fluff can usually be found well into the autumn, thus enabling the determination of the sex of a tree well after the flowers have disappeared on the trees.]

When I get a ‘phone call or e-mail from the other side of the county asking me to check out a BP I first of all ask if it has any spiral galls on the petioles! This is not an infallible indication of betulifolia because they are equally abundant on typica,  ‘Italica’ and ‘Plantierensis’ but it does rule out any contribution from deltoides. If it is one of the P. nigra group, the spiral galls are usually very abundant, commonly as many as 2 and up to 6 per petiole. Leaves with spiral galls usually drop first in the autumn, and can usually be found recognizably in the leaf litter throughout the winter.

I should point out that P. spyrothecae will not attack trees that are water stressed. It’s possible to find a tree smothered one year and the next either none at all, or only literally a handful, if the tree is suffering from drought. A further indication of drought symptoms is leaf size. A heavily pollarded or crown reduced tree may produce very small leaves for several years during the recovery phase, and may take up to five years before it recovers the ability to produce flowers.

Where do they Grow??

Although having evolved as a wetland tree, rather like ferns they can be transplanted or cloned vegetatively onto dry sites. Although most trees are planted near water (usually in groups) most isolated trees are found where they have been planted in quite dry sites. Formerly grown on farmsteads, often near the farm buildings or farm ponds, as a timber tree, and cloned repeatedly when harvested or pollarded for poles.

They are occasionally bundle-planted in large numbers along streams/hedgerows (Hannington, Wiltshire) or in plantations (Woolwich Ordnance factory). Nowadays they are often found near the entrance to industrial estates established on old farmsteads. Often found in small numbers amongst later additions of hybrid trees in dry areas. They may also have been planted in long lines along river banks in the early 20^th C, e.g. Upper Thames. Nowadays frequently planted in large numbers as lines or avenues, in parkland, often ridiculously close together. 

In towns and parks ornamental P. nigra often gets treated like a Hybrid Lime or London Plane. If they are regularly mop-head pollarded most withstand it O.K. but if significant crown reduction or pollarding is carried out on a tree that has missed several cycles the exercise is frequently fatal.

Most trees are pollards, either low (2-3ft) or high (6-8ft) and up to 10 poled. A few formerly planted along rivers or in marshland that has now scrubbed over, have now formed tall majestic maidens up to 100ft high, or have fallen over repeatedly and formed naturally cloned groups. In towns they have frequently been planted as street or parkland trees and are heavily mutilated by crown reduction, often with fatal results. Very often only single trees are reported, and appreciable numbers are then found on further investigation. Often one large pollard or maiden has been used as a clone-parent in a local cluster.

Locating P. nigra betulifolia.

One might think that an 8-figure grid ref: e.g. TL685,660 i.e. a 100m square reference would be adequate to relocate a tree!

How wrong you can be!  Why? Let’s discuss.

Firstly, many people can’t identify a Water Poplar, so many of the records held in BSBI recorders vice county data bases are either hybrids or Lombardy Poplars. And few vice county recorders bother to check them out fully. Thus using a Vc listing as a starter can result in one spending a whole day trying to find a non-existent tree or trees.

Most records made in the field are made by recorders using 1:50,000 maps, and features such as roads are dimensionally exaggerated so that the grid ref may flag up the wrong 100m square. Even if 1:25,000 maps are used, ‘estimating’ the tenths across a 1km square rather than measuring them can also result in the wrong 100m reference.

Many people do not realise that the first 1km line of a 10km square has a zero notation, thinking it to be a 1, thus pushing the ref. either one km too far east or one km too far north. Also, be prepared for 6s or 9s being transposed, or the fourth and fifth and sixth and seventh figures of an eight figure reference having been accidentally transposed while the mapee searches for something to measure the tenths across. [I can supply a transparent overlay for reading maps grid refs. At all scales]

Reproduction in P. nigra

Water Poplars can reproduce in three ways, by seed, and supposedly by branches breaking off and flowing downstream – but the third method – the most effective of all is seldom mentioned in European literature, - probably because it is now largely suppressed by human activity, and that is clonal suckering from the roots and from adventitious buds.

Ultimately most Water Poplar in a damp situation fall over – and along comes man and removes them – or, they snap off at the base – and man comes along and chain saws off the stump.

In a wildwood flood plain forest however when trees fall over, if they snap so that there is still continuity with the basal root system, adventitious buds along the trunk sprout, and develop into new trees. Gigantic trees can develop along the trunk, and as the trunk eventually rots or/and sinks on its lower side the adventitious trees take root through the old trunk.

If the old trunk is hollow it will collapse earlier, and the adventitious buds may give rise to a line of 10-20 small saplings, all rooted in the rotting remains of the old trunk.

If the old trunk falls on dry ground, or it snaps right off, providing the stump has not been chain sawed off it will re-shoot either from adventitious buds above ground level or from root suckers.

In Wiltshire in 2009 I discovered a fallow arable field with numerous root suckers 5-10 meters into the field arising from two huge males of clone 28 in a nearby hedge. Their shallow roots must have been damaged each time a plough or harrow was dragged across them, providing the stimulus to generate suckers. Similarly at Chickney in Essex three heavily stressed female hedgerow pollards produced a row of saplings from root suckers along an adjacent ditch. At Aveley in Essex, a stressed heavily pollarded male produced root suckers under a roadside bank that have now given rise to two new trees. At the Woolwich Ordnance site, in Greenwich, a large grove of male Water Poplars was contaminated with gas works waste late last century. Thousands of root suckers have now given rise to large numbers of saplings in a ring around the contaminated patch.

Even if the trunk is snapped off completely, providing it is not chain sawed level with the ground, shoots will sprout from the root crown and from adventitious buds around the stump itself and one of these will ultimately dominate and regenerate the tree. And some of them can be cut off for sets.

Suggestions for Conserving Water Poplar Genetic Diversity

Avoid attempting to cross any male and female clones until information is available to assess their individual disease susceptibility. Otherwise we could be diluting any residual genetic differences in disease resistance (e.g. cuticle thickness/hairiness).

Similarly try and avoid planting different clones together until we know more about their relationships and their local propagation history. The spores from a heavily infested tree might overwhelm a nearby tree of a different but more resistant clone that could otherwise fight off a mild infection.

Attempt to propagate about 20 of each local veteran clone in the same catchment as you find it – not closely spaced avenues, or rectangular grids of hundreds of trees! Most of the Water Poplars in Britain are mutilated by coppicing, pollarding and more recently crown thinning, yet some of our oldest trees are gigantic maidens, and are not given enough room to show their full glory. Avoid using small cuttings, a truncheon will give you a 3-4 year head start and has a much greater chance of success.

Try not to bother with a clone bank, you can usually get up to 30 truncheons from a known veteran tree. Apart from trying to establish a cutting in a clone bank, you will have to restart cuttings for elsewhere. And you run the risk of the original cutting  dying, being accidentally mislabelled or the label being lost. 

Decide where you want to plant your next generation trees for a given clone and then take truncheons from the veteran and plant them directly, just like you would a cricket bat willow. When selecting branches for a truncheon pick those growing vertically and with the longest annual growth segments (well over a foot in the last year), they will be the youngest and most vigorous. If you chose less vigorous branches they will be in the senescent phase and will appear to be O.K., flowering in the first year, and then snuffing it!

Select a terminal branch (stand on top of a Land Rover with a long lopper!) and trim it to 5-6 feet long. Trim off all the side shoots, just leaving a small terminal tuft. Take it to the site you want to plant it as soon as possible – chop off 3-4 inches from the basal end to unblock the vessels, point it up with a bill hook and push it into wet ground at least one foot. [just like a cricket bat willow set]. If one of your veteran trees falls down, you are in clover! – it will produce numerous vigorous shoots along the trunk that you can use for truncheons – providing you don’t chop it up!

Sampling for DNA fingerprinting.

For each tree you wish to sample, take half a dozen 18inch long terminal twigs with recently unfurled leaves and quickly wrap in a super market bag to keep them moist. When you get home, cut them down to c.1ft lengths to remove the blocked stems which seal off rapidly in the open air, tie them together with string and add a label, and immediately place them in a flask of water. Accumulate around 20 to 25 samples over say a week of searching, and check as you go along that they are not wilting in the flasks. If they are, cut a bit more off the stems. Finally at the beginning of a week, cut them down to around 6 inches long and pack them in sets of shoots in 10 x 12inch Tesco self- seal bags, then pack all 20-25 in a cardboard box, and do a special Royal Mail overnight delivery to Forest Research at Roslin. Previously having phoned or e-mailed to ensure that someone will be there to put your samples in the freezer when they arrive early the following morning. N.B. the charge per tree for DNA fingerprinting for 2012 is £50 per sample.

Aerial Images and 12 Figure Grid References.

For these you can use Goole Earth in combination with Nearby.org.uk which will give you accurate grid references. Or you can use ‘the site ‘Wheresthepath’ which gives you a moving display of the 12 figure grid ref. as you move the cursor. [http://wtp2.appsspot.com/wheresthepath/htm]. If you press Ctrl followed by PrtScn your computer will put the image of the screen on the clipboard. You can then paste it into say PaintshopPro, select the bit you want and annotate with your BP information.

HAPPY HUNTING