(Arboricultural-styled) 'Fact of the Day'

[Kveldssanger]

Ah man, quite a few typos...

[Kveldssanger]

15/04/16. Fact #191.

 

In an age where life is rather tumultuous and detached from nature, many individuals may opt to visit woodlands and forests as a means of escaping from the frenetic day-to-day living of an urban environment. In fact, alongside the rise in urban populations there has been a rise in the number of individuals using woodlands and other green areas, and such a growing desire to visit has led to these sites becoming highly-used and thus pressured. Sites nearby to urban fringes, and those that are readily accessible via transport means (cars, trains, etc) may be most readily used, given that there is only so much time in a day and many individuals will only visit such sites for a few hours (oft during fair weather) before returning home.

 

To probe further into exactly what drives woodland visitation by individuals, we can look at a new article published in the journal Urban Forestry & Urban Greening. This specific study looks at woodland sites in Wallonia, Belgium, and delves into who visits woodland sites (demographics), and how they get there (transport). The region of Wallonia is covered by woodlands (around 30% of total land cover), and these woodlands are found quite far from any major cities (75% of woodlands are located in rural locations). A total of 40 sites were used for the study, and 14% of these were in peri-urban or urban areas. These (peri-)urban sites accounted for nearly 50% of all surveyed participants. Results from the questionnaire are shown below.

 

Who visits Belgian woodlands, and how do they get there?

 

From the above data, we can spot some very interesting things. For instance, many more people visit woodlands during the weekend, suggesting that the visits are undertaken outside of typical working times. Given the average age for visitors to the woodland sites is far below the retirement age, we can safely assume that this is the reason for the preference of weekend visits. This assumption is further supported by the fact that 68% of all woodland visitors are currently employed. We can also observe how the fewest number of visitors visit the woodlands during autumn, which is actually somewhat curious as autumn colours are absolutely stunning. It is arguably not at all strange, however, that the spring months attract the greatest number of visitors, though winter-time visits for walkers is actually higher (by a few tenths of a percent).

 

In terms of how people get there and who with, we can see that there’s generally a mix of sole individuals, families, couples, and groups who frequent the sites, though this is not really where it’s particularly interesting. Instead, it’s when we look at how they get there that it gets quite cool. For example, we can observe how sole individuals will access the woodland by foot or via bicycle, which is likely because of the ease of access via such means. Driving a car is probably not so enticing, as there’s less of a push for time and fewer people to suit on the trip, so it’s not as if once a child gets bored and starts throwing a tantrum that the entire family has to go home – there’s more freedom involved with accessing the woodland. We can also spot how a good third of families will cycle to a woodland, indicating that there is a desire for a family outing to coincide with a sort of ‘keeping fit’ mentality. Granted, cycling may generally be more feasible for families with slightly older children, as toddlers, whilst able to cycle, cannot cycle too far, and nor is it probably practical to have a young child cycle to a woodland unless it’s very close by (which isn’t usually the case, in this region of Belgium).

 

There is a general trend of people going to woodlands to relax, as well. Unsurprisngly, this markedly changes for those who cycle, where it shows that over 95% of those who get to the woodland via bicycle will go there for a sporting purpose. This adds weighting to the idea that families who cycle there have older children (or even a family comprised of only older generations). Such a disparity in results for those who cycle is however surprising, as it suggests only 2% of those who cycle to a woodland do so in order to relax. Perhaps there is no such thing as a leisurely bike ride, therefore?

 

The male:female ratio of woodland visitors is also quite distinctly different. According to this study, a good two-thirds of visitors are male. This ratio stayed true for the means of access to the site being on foot or via car, though rose sharply to 88% in favour of males if access to the woodland site was via bicycle. Maybe this has something to do with the high use of woodland sites for sporting, when the visitor arrived via bicycle. On a broader scale however, the reason for fewer females visiting is curious. Perhaps it has something to do with females feeling more wary of being alone in woodlands, or instead preferring to visit other places during free time.

 

Maybe cyclists arrive at woodlands in order to race or ride with or against other cyclists. Source: National Trust.

 

With regards to the distance travelled to get to the woodland, the data provided is not really eyebrow-raising. An average walk of 4km to get to a woodland site is somewhat fair, and it cannot be thought that anything other than a car journey would bring in the highest distance travelled to reach the desired woodland site. Walkers spending the least time (111 minutes) at a woodland is therefore not surprising, as they’ll spend probably the most time either side of their visit getting there and back. Walking will also expend the most effort in travelling (though not necessarily the most calories burned, which likely is held by those who cycle). Despite this, an average stay of 137 minutes (a little over two hours) is quite reasonable, and suggests that visitors seek a more instant impact in place of spending a whole day on site. Of course, the size of the woodland would have an impact, in this regard. If you’ve walked an entire woodland in around two hours, you may as well go home, after all. The purpose of the trip also defines the length of stay, and as it as generally the case that people were there to relax (excluding cyclists – though sporting is a form of relaxation or recreation) then dragging-out a stay may end up being stressful, as remaining somewhere only for the sake of remaining there is counter-intuitive.

 

If you want a more detailed breakdown of this paper, then I advise you locate a copy. I downloaded the entire journal whilst it was temporarily set as Open Access, though it appears to have once again been ‘closed’ (as of yesterday). It’s a good read, and not too heavy on the science-y stuff.

 

Source: Li, S., Colson, V., Lejeune, P., & Vanwambeke, S. (2016) On the distance travelled for woodland leisure via different transport modes in Wallonia, south Belgium. Urban Forestry & Urban Greening. 15 (1). p123-132.

[Kveldssanger]

22/04/16. Fact #192.

 

Some info on UK case law, trespassing roots, and subsidence.

 

Roots can be removed to the boundary in the same manner as overhanging branches can, assuming removal is done with reasonable care. As per Lemmon v Webb [1894], it was held that a neighbour could cut back from his property without notice to the owner of the tree, provided that he could do so without entering the owner’s land. In the case of McCombe v Read [1955], such a ruling was again found, where the judge remarked that a neighbour could indeed cut back any root encroachment back to his or her boundary. Furthermore, the judge even ruled that the defendant who owned the trees must ensure that the tree roots did not encroach unto his neighbour’s land so that they could be deemed to be once again causing a nuisance. Soon after, the judge in Davey v Harrow Corp. [1957] ruled similarly, by remarking that “if trees encroach, whether by branches or roots, and cause damage, an action for nuisance will lie”, though only if the apparent nuisance was indeed reasonably recognisable (for trees existing close to boundaries, such an issue almost certainly is). More recently, this precedent is evident in Perrin & Anor v Northampton Borough Council & Ors [2006], where it was ruled that “root encroachment into a neighbouring property was similar to bough encroachment, and that the neighbour could lop boughs or grub roots without notice“.

 

This is not reasonable, in terms of current case law precedent. In severing these roots on the tension side, the line of trees were left at significant rsk of windthrow.

 

Beyond mere direct encroachment and subsequent nuisance abatement, the most significant factor surrounding root encroachment onto a property is subsidence, where the soil is shrinkable in nature. In 1940, the case of Butler v Standard Telephones and Cables was one of the first to deal with the subsidence issue, and it was ruled that the line of poplar trees grown on the Company’s sports field, which were subsiding the claimant’s property, were the culprits. The line of defence the Company adopted was one of not being able to foresee that the poplars would cause such damage, though even whilst the judge did remark that the poplars were very attractive specimens, it was ruled that the Company should have appreciated the destructive potential of trees. Therefore, their defence was dismissed, and the claimant won the case. This ultimately sets the shape of things that were to come, as the precedent set was one of outlining how a tree owner must be able to recognise that trees, by virtue of their mere presence, can cause problems. Failing to recognise this and deal with such problems appropriately is, therefore, negligent.

 

In recent decades, the case of Solloway v Hampshire CC [1981] continued this precedent, and ruled that where harm as a result of the moisture uptake by encroaching roots was foreseeable, action must be taken to reduce the nuisance. This case, in essence, saw the claimant’s property subside as a result of the Council’s trees, though as the area was predominantly considered to reside upon gravel, the Council had no knowledge that small pockets of clay underlay the claimant’s property. Therefore, whilst the initial judge ruled the Council were liable, at appeal it was ruled they were not, given such a geological erratic was not foreseeable: “To say that a risk of damage is reasonably foreseeable means that it is foreseeable, not merely as a theoretical possibility but as something, the chance of which occurring, is such that a reasonable man would consider it necessary to take account of it.” The judge, at appeal, also ruled that nothing short of felling the trees would have satisfied the situation, and because the Council would have not known that these trees were causing such an issue, expecting for them to have been removed prior to the issue manifesting would have been unfair and disproportionate to the level of foreseeable risk.

 

With further regards to the issue of subsidence, Delaware Mansions Limited & Others v Lord Mayor & Citizens of The City of Westminster [2001] ruled that: “The encroachment of the roots was causing continuing damage to the land by dehydrating the soil and inhibiting rehydration. Damage consisting of impairment of the load-bearing qualities of residential land is, in my view, itself a nuisance.” In addition to this, the case stated that the established nuisance would continue up “until at least the completion of underpinning and piling“. Perhaps more importantly, this case continued the precedent that unreasonable and unacceptable burdens on local authorities and other tree owners must not be placed. It is not acceptable for unforeseeable harm to be anticipated and acted upon, by the owner of a tree. This precedent indeed relates back to Leakey v National Trust [1980] and Solloway v Hampshire CC [1981], where it was stated that only where harm is foreseeable can a nuisance be abated. In more recent times, this precedent has been echoed by Berent v Family Mosaic Housing & Islington Council [2012], where it was ruled that subsidence damage caused by two mature plane trees was not a foreseeable threat, and again with Denness v East Hampshire DC [2012] and Robbins v Bexley LBC [2012]. In the case of the latter, the defendant took the issue to appeal, where it was still ruled that they were liable for damage associated with tree roots (from two hybrid black poplars) causing subsidence, given they had not managed the trees in any manner for the period between 1998-2006, and only after this point had they enacted a four-year management cycle for the trees in question – all whilst the risk of subsidence was foreseeable.

 

A line of large poplars adjacent to a factory unit. In this instance, is the risk of subsidence foreseeable?

 

Despite this, where harm is foreseeable, local authorities and owners must act (as already established). This applies also to ‘managing agents’ of a tree found to be causing damage. For instance, the judge in Le Jones (Insurance Brokers) Ltd v Portsmouth City Council [2002] ruled that, where Portsmouth City Council were managing the tree stock of Hampshire County Council, “I do not understand on what basis it can be said that Portsmouth did not owe the claimant a duty to perform its function of tree management with reasonable care. Mr Bebb boldly submits that the only duties owed by Portsmouth were to HCC, and that only HCC owed a duty of care in tort to persons who foreseeably suffered damage as a result of inadequate tree management. I do not agree. The mere fact that Portsmouth owed a contractual duty to HCC does not mean that it owed no duties in tort to anyone else.” As a result, Portsmouth were found part-liable for the damage caused by root-induced subsidence, though it should be noted that a formal agreement was in place between the two parties that outlined the defendant’s role in managing the tree population for Hampshire County Council. Where such a formal agreement is lacking, there appears to be no current guidance on how a ruling would be made.

 

It must however be stressed that adequate proof must be provided in instances of subsidence, as concluded in Hilda’s Montessori Nursery v Tesco Stores Ltd [2006]. Adequate proof is, according to experts and the conclusions of the case, at least one year’s worth of monitoring and the associated data. In Loftus Brigham v Ealing Council [2008] however, it was concluded by the ruling judge that it must be established that roots must be the “most dominant” cause of subsidence-related damage, not simply one of multiple causal agents. Interestingly, this case was overturned and sent for retrial, as it was deemed the judge was incorrect in his conclusions and that burden of proof was not on identifying roots as the “most dominant” cause, but merely a cause. Such identification of whether a tree is merely a cause relates back to Murray v Hutchinson [1955], where the judge stated that one must “not jump to the conclusion that because they have a bad name they are always responsible for this damage.” It was ultimately ruled that the tree was found to play 25% of the role in harm caused to the property, and damages were awarded in light of this. However, the judge in Mayer v Deptford and Lewisham Councils [1959] ruled that, even though a plane tree was found to only have accelerated subsidence damage once it had already begun to manifest via other means, full damages were to be paid, by the defendant, to the claimant.

 

In situations where more than one tree is found within an area known to be subsiding, care must also be taken to identify only the trees that are causing the damage. This precedent was established in Malewski v Ealing LBC [2003], where it was argued by the defendant that trees within the garden of the property were causing the damage to the foundations. Ultimately, it was concluded that the highway tree owned by the defendant was the cause, though the precedent set on accurately proving implication of a tree was critical.

 

As a somewhat aside, the case of Siddiqui v Hillingdon LBC [2003] found that damage had occurred via the removal of trees prior to development, and not from existing roots on site. The claimant had alleged that the cracking was due to soil desiccation, though it was ruled that the cracking was in fact down to heave (resulting from the removal of trees prior to development). Such a case acts as a reminder that exiting trees may not necessarily be the cause of damage. However, perhaps more importantly, the judge ruled that “modern standards of construction can be expected to take account of obvious hazards in the vicinity of the structure to be built…“, which may have implications for future claims where subsidence is an issue for newer builds on sites where trees were retained. Current case precedent does also recognise that the severance of roots may cause heave, as outlined in Park v Swindon BC [2011].

 

As another partial aside, the case of Kirk & Ors v London Borough of Brent [2005] set a possible precedent for a retrospective damage claim against the owner of trees considered to have been causing subsidence. Some years earlier, a line of properties had to be underpinned as a result of suspected subsidence damage, resulting from the moisture uptake of trees owned by the London Borough of Brent, though the Council were not notified of the underpinning works until after the work was entirely completed. The original judge rejected the claim, though on appeal it was determined that, even though there was no exact proof of the subsidence being caused by the trees, the Council should pay damages amounting to £15,000. In fact, this case influenced a more recent case where a near identical situation occurred, which was that of Robbins v Bexley London Borough Council [2012]. The High Court held that even though the local authority had not been notified of any damage to the property, the damage was still reasonably foreseeable as the trees had caused damage to other local properties and, once that was known, proactive remedial action should have been taken. When taken to appeal by the defendant in 2013, the case precedent remained as per the original ruling, and the appeal was therefore dismissed.

 

Other issues caused by roots, such as damage to drains, is outlined in Kennedy v Bournemouth Borough Council [2012], where it was determined that the roots were not the principal cause of the flooding caused by blocked drains, but instead the principal cause was that of the state of disrepair with the drain pipes themselves. The court decided that the claimant was responsible for making good the drain pipes, so that tree roots could not exploit the cracks for moisture.

[elspedo]

Evening, where are you getting your legal references from? I'm writing an essay for my degree at the moment and finding legal references hard to come by.

 

Cheers

[Kveldssanger]

Principally Charles Mynors, though also had a solicitor who deals with tree-related cases give me and a few others some info with regards to subsidence and tree management.

 

I also took a look at some of the actual cases where they were available in PDF / as text.

[elspedo]

Looks like another book needs adding to the Amazon wish list then!

[Kveldssanger]

Honestly, if you're doing a degree and this is an essay of yours, I'd say you'd need to at least loan out the book (2nd edition!) from a library. The LTOA has a bit of info on case law, though Mynors goes into so much depth that it really does cover most things to some degree. Granted, it's not gospel, though it's certainly highly valuable as source material.

[Gary Prentice]

Chris, could you email me a copy of the subsidence post and the other legal post, when convenient.

 

They're good reference material as I aways forget what case I want to reference to or refer to.

 

Thanks, Gary

[Kveldssanger]

I sent you an email with what I have, Gary. It's my coursework, which I have pretty much pasted here as common law is a bit of a bugger for many and finding info is hard if you don't have Mynors' book.

[Kveldssanger]

24/04/16. Fact #193.

 

I’m currently engrossed in Vera’s book Grazing Ecology and Forest History, which I cannot rate high enough for its readability, lucidity, and coherency. Whilst on my holiday last week, I read through the third chapter on the study of palynology and how this relates to interpreting how treed landscapes may once have looked, and I have to be honest when I say that the entire field was somewhat (though not wholly) new to me, and what was suggested within the book certainly made me think. For this reason, I’m going to write a little bit about pollen studies and how it can effectively be used, or even ineffectively used, to determine what our landscapes once looked like, with regards to what trees existed, and in what abundance / distribution, according to Vera.

 

Vera begins by ‘setting the scene’, by describing how the Swedish geologist, Von Post, in 1916, produced what is considered the first pollen diagram. Prior to the utilisation of pollen, typically accumulated in peat bogs and lakes (which are regional pollen sinks), larger parts of plants were used in an attempt to understand what the landscape once looked like (up until the last Ice Age some 12,000 years ago) – leaves, fruits, tree stumps, and possibly even larger seeds were three means of how the landscape’s vegetation history was being deciphered, and again these were usually found within peat bogs. In this sense, prior to 1916, the vegetation composition of a landscape was being understood through assessing how plant macro-fossils were distributed (vertically) in peat bogs. For example, if a stump of a pine tree was found below the leaves of a willow tree, one could suggest that pine trees existed prior to willow trees in the geographical area. After 1916, pollen, which readily remains desposited in such aforementioned naturally-occurring sinks, could instead be used. Granted, pollen generally only persists for wind-pollinated species, with the exception of poplars, so one cannot, in theory, decipher the exact presence of tree (and plant – grasses, etc) species – one can instead only interpret, based on the facts gathered.

 

By-and-large, following Von Post’s landmark pollen diagram in 1916, studies into pollen presence had suggested that the landscape was once almost wholly covered in trees (where tree cover was possible, due to biotic and abiotic factors). This is because, when pollen studies have been undertaken, the large majority of pollen found has been from tree species (usually, non-arboreal pollen amounts for no greater than 5-20% of total pollen in the sinks). Historically, and prior to 1934, when Firbas published a paper on how one can also identify and use the pollen of grasses and shrubs to determine landscape composition, there was also a choice to ‘ignore’ the pollen of non-tree species. Because of these factors, scientific opinion was generally that grasslands and wood pastures are an advent of agriculture and man’s influence upon the landscape, in place of wild ungulates (auroch, bison, boar, deer, Przewalski’s horse, and so on) influencing upon the vegetation composition. Therefore, prior to modern man, the European and American landscape was largely void of expansive steppes and pastures, where the land was potentially habitable by trees. The wild ungulates were thus not seen as responsble for carving the landscape, and thus only existed in low numbers within treed landscapes. Instead, these wild herbivores followed the regression and regeneration of trees in the landscape.

 

An artistic depiction of the auroch (Bos primigenius). Interestingly, the breeding of cattle in an attempt to re-create the auroch is being undertaken, by breeding characteristically-similar (to the auroch) domesticated cattle and allowing them to exist in the wild. Image source: Open Up!

 

However, where it gets interesting is when one looks at what tree species were present in the pollen records. Before we look further at this however, we must recognise that the dense forest will generally be host only to shade tolerant tree species (beech, lime), assuming it has reached its ‘climax’ (prior to this climax, more light-demanding species will be present, initially with birch, hazel, pine, willow, and so on, and then with species such as oak). For this reason, if we assume that the historic landscapes were covered with high forest, we can assume that much of this high forest will be of climax species, as man was not historically around to carve apart such landscapes with cattle and for arable activities. Despite this, this is not what the pollen records show. In fact, hazel (Corylus avellana) and oak (Quercus robur) contribute quite significantly to pollen records, and as neither species will regenerate in high forest (because they are not shade tolerant), how is it possible that large tracts of the landscape were high forest? Unless the species were able to regenerate significantly enough in high forests to feature so readily in pollen records, which goes against the species’ understood biology and ecology, there must have existed landscapes where significant light was able to reach the floor. This is where Vera suggests that the landscape could very well have been shaped by wild grazing animals, who kept large areas adjacent to groups of trees or forests open (where there was the ‘mantle and fringe’ vegetation), and the thorny scrub that grew within such a grazed landscape enabled for hazel to grow in thickets and oak to succeed within such thickets (of hazel, and particular thorny scrub, on which ungulates would not generally graze). Oak, in particular, can in modern day be observed not to regenerate in high forest, but in grazed areas amongst thorny scrub (I myself saw this the other day at Dunwich Forest and nearby heathlands, where oak was regenerating not amongst high forest, but within the gorse and bramble scrub).

 

A young Quercus robur growing amongst gorse and bramble, and protected from the impacts of grazing as a result.

 

Vera also raised concerns over interpreting the high amounts of tree (arboreal) pollen in pollen records as meaning the landscape was largely comprised of trees. This is because the pollen sinks, as already stated, are generally regional (peat bogs and lakes, of which large lakes are more often used). Because tree pollen is released early in the season, and is usually released in high abundance at an elevated level in the canopy, there is a much greater chance of tree pollen travelling greater distances, where it will reach these regional pollen sinks. Conversely, grasses release pollen during the summer, and at levels just above the ground, where winds are less strong and there is a greater chance of the pollen not travelling too far (because of the lower wind speeds, and the trees and shrubs in leaf ‘trap’ the pollen in situ). As a result, a regional sink, such as a peat bog, even if large areas of land, even almost adjacent to the bog, were grassland or pasture that were bordered by trees, there is still a very high probability of non-arboreal pollen not accounting for more than 10-25% of the total pollen distribution in a sample. Not only this, but even if we assume that the landscape was wood pasture where animals grazed, the suppression of the grass by grazing herbivores and the fact that open-grown trees have much larger, fuller crowns, means that pollen ratios between arboreal and non-arboreal sources will likely register as if the area was instead a forest (for example, the total crown area of an area of wood pasture and of high forest may not be all that different). Trees in wood pasture will also have more clearance for pollen to travel great distances, and thus end up in these regional sinks at high levels. Even modern-day records suggest exactly this, and in this sense a wood pasture can be interpreted as, if assessed on pollen records alone, high, dense forest. Of course, this suggests that pollen records only tell part of the story, and it is easy to mis-interpret findings based on pollen studies.

 

What could be considered mantle and fringe vegetation (regenerating birch amongst gorse), with Dunwich Forest’s pines in the background. Bear in mind deer (at least) are found on the site, so there is some grazing pressure.

 

If you have found this post interesting, then please do consider buying the book. There is no way that I can give the whole picture here, and instead I have only given a fragment. Hopefully, it makes sense, and hopefully it gives an indication of why suggesting that the landscape was once comprised of massive expanses of high forest is perhaps not entirely accurate. In the modern day, there is no doubt that grazing by cattle has suppressed the regeneration of forest, and man’s conservation efforts with heathlands and grasslands has also stopped forest regeneration; as has man’s carving-up of the landscape for building and development. However, historically, when wild herbivores were still actually in existence, as man hadn’t pit-falled the last auroch to its death, the landscape may have not been covered exclusively by high forest where conditions allowed. Considering that fire is not seen as a massive driver behind the regression of forests to grassland and then back to a form of woodland at a later date, and the beaver is not considered to have been the only mammalian influence behind the loss of forest patches (again, according to Vera and the sources he immersed himself in), perhaps wild ungulates had more of a role in shaping the landscape than is generally considered. Food for thought, no doubt. Graze on that literary resource, and head out for pannage in your local library.

 

Source: Vera, F. (2000) Grazing Ecology and Forest History. UK: CABI Publishing.