Identification of Tree Roots

Your top 10 questions answered:

  1. Why? To provide evidence for the origin of roots found during investigations into damage to buildings or installations. Are they from your tree… a neighbour’s… the local council’s…? In English law it is the owner of such a tree (or his house contents insurer) who is responsible for any associated reparation of another’s property.
  2. Who? Most of our clients are professionals involved in the investigation: Structural Engineers, Surveyors, Loss Adjusters, Tree Consultants… but we also accept jobs from private individuals, following an advisory discussion.
  3. Where from? Trial holes are dug in a sensible place (not necessarily under a crack in the wall, but better where most structural movement has taken place in order to produce the crack). A deep excavation, to at least under the footings, is strongly advised. Bore holes can also produce roots - to 5 metres or even more! Blocked drains can yield masses of fibrous roots. NOTE that drain roots must be sterilised in hot bleached water for 10 minutes then dried before posting.

  Cross section of
  a Lime tree root

  1. How? You send us the roots. We prepare them, cut very thin slices around 20 microns thick, then examine these under the microscope. We assess the best match for their anatomy: their cell-layout and -structure; no two roots are identical, and thin roots can have very limited structural features, but within the constraints of the following paragraph we can normally assign them confidently and accurately, based on our long experience in this field.
  2. What sort of sample? Any root over about 0.5mm diameter is attempted, and 50mm length is plenty. Please retain the bark on any specimen as this is usually essential for identification of the root (note how different is its structure from the 'wood' of the root in the adjacent photograph of a Lime tree root). Do NOT keep damp samples in plastic bags, as they can rapidly decay, especially in a warm office, whereas clean, dry roots last for many years virtually unchanged. We keep short lengths of all roots for six years to allow for any subsequent queries. Do not hesitate to send a good representative number of roots from each location; we only fully process those which are distinctive to the trained eye through hand-lenses (reporting that others ‘appear similar...’), not an infallible procedure but sufficient for most cases, and certainly a money-saver; we are always prepared to return to the rest if the need is justified!
  3. How many sorts of root are there; how many can you identify? Over 140 different types of root can be distinguished. Some are specific to a single type of tree or shrub, while others are referable to usually small groups of closely related types. Almost 90% of broad-leaf trees can be assigned to their genus unambiguously or at most to a pair of alternatives. For details check out our list of identifiable tree and shrub roots. Sometimes for shrub roots we will not be specific, as there are many rare types for which documentation is inadequate; for these, or indeed for roots that are very immature or atypical in structure (perhaps diseased, decayed, distorted) we can only say with confidence what they are not, which can still be useful - and if you want to take it further, we can almost certainly assign the sample to a particular shrub, following receipt of twig samples from you of all nearby woody plants.  See under plant identification [appropriate samples] and subsidiary information for further information.
  4. How long does it take? Our report is issued on average 6 working days* after receipt of the roots. It is sent by first class post, and can also be e-mailed or faxed. Very urgent jobs can be done faster, though usually associated soil testing dictates the overall timetable.          *(Based on our records since 1992).
  5. Are our reports authoritative? We are the most experienced organisation world-wide in respect of root identification, having issued some 95,000 identification reports since 1979; they are accepted by the courts and in insurance claims.
  6. What does it cost? This depends on the number of packets of roots supplied from a site. For 1 to 2 packets from a site, the charge is £100 (add £20 if Iodine testing is required). The charge for 3 to 4 packets is £150 (add £30 with Iodine testing). All charges plus VAT. Please contact us if sending 5 or more packets from a site. Most private jobs consist of just 1 packet of roots. Discounts are available for larger suppliers (please contact us). New or first time customers must send payment with samples. Payment is accepted by Sterling cheque or via direct Bank transfers. Overseas payments: a 15% charge is added to cover international Bank fees. Your Report will be emailed; should you require a paper copy, please let us know - we will provide one at no extra cost.
  7. What other information can be obtained from root samples? See subsidiary information, which includes details of the most commonly requested further test on roots, the iodine test for starch, as well as a note on DNA testing and other observations.
  8. Yes, OK, one for luck:  Do we want clues, to assist us in our identifications?  No!  For two main reasons: i) We must be seen to be objective, and not influenced by any prompting, and we will contact you if we feel, in exceptional circumstances, that futher samples would be useful (see answer 6. above); and ii) We have to admit that a very significant proportion of so-called clues are inaccurate, based on misidentification of the suspected source tree or shrub by those who have visited the site. Believe it or not, there are cowboys out there who can only 'identify' roots if told what's there beforehand! 

Should you have technical queries in fields peripheral to the above, consult our useful links page.

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