Removing Trees Close To Your House
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Should I Remove A Tree Close To My House?
Have you asked: Should I remove a tree close to house? We look at whether it matters if trees grow close to your home. Find out more about the problem with trees and buildings.
Does it Matter if there are Trees Close to Your Home?
Trees achieve their maximum amenity value once matured and can take 50 years to do so. These mature trees are irreplaceable and offer a multitude of value, especially so in built-up areas.
In terms of whether a tree is directly causing damage to your house or property is typically obvious; whether it will is less obvious, but generally depends on these three factors:
If the tree roots can grow under or are already under foundations and pipelines. (Can cause subsidence)
The ability of said root systems to abstract moisture.
If the tree is dead.
A certified arborist is the most qualified to make these assessments and judgements for your specific situation.
What is The Problem with Trees and Buildings?
While in most cases, trees pose no threat and cause no damage near buildings even when growing, some instances can be linked to tree roots. Instances include; structural damage, subsidence, lifted paving and blocked drains.
Understanding the factors and damage involved, such as soil type, harm to buildings, depth of foundations and more, can help determine what actions to take or when to contact local tree services or tree care professionals for advice.
Typically only an issue for shrinkable clay soils. This is most common for buildings up to four storeys tall, constructed before the 1950s, due to common shallow foundations. Buildings post 1950s are relatively safe from this issue.
Roots, while rare, have been known to grow into drains and block them. Older drains, especially those with poor seals or rigid joints, are vulnerable to leaky drains; leaky drains can form cavities in which water will flow into the soil.
Stems, branches and other parts of large trees can cause damage to roofing or gutters, such as from impact, clogged gutters, pruning, trimming, additional weight and more. Expanding roots and suckers can lift lightweight objects or structures and paving, such as sheds or garages. It is worth noting that due to the composition and nature of expanding roots and suckers, that they're unable to lift heavier objects or structures.
How Can Tree Roots Cause Problems?
During extended periods of drought, trees can dry out shrinkable clay soil, causing the soil to shrink; the issues come in when the soil under the foundation begins to shrink. Shrinking peaks during the summer months, deemed 'seasonal soil moisture deficit', due to drought and the chance for winter rains to rewet the soil. This shift in the soil can cause subsidence of the foundations and cracks within the building or structure.
Movement of around 5 to 10mm will often create cracks, usually near doors and windows. While less common, permanent soil moisture deficits can occur, in which soil perpetually gets drier at depth, year after year. If you were to remove a tree due to this, you risk causing heave (Foundations moving upwards due to expanding rather than shrinking).
Roots by nature, once in contact with anything solid, will naturally redirect themselves to the path of least resistance, thereby causing no damage or threat. Exceptions to this are when limited space is available near a structure, and tree trunks expanding may provide enough force to displace or shift heavy structures.
Roots by nature, where water is accessible, will proliferate; this exact nature causes roots to grow within drains. Watertight drains help prevent access, and as such, roots won't be attracted to them; Trees should be planted 15 feet away from drains where possible, or drains should be made to be watertight.
Direct, Indirect or Potential damage
Direct damage is defined as harm caused by the mechanical action of any segment of the tree in direct contact with any segment of a building or structure. Contact may be defined as consistent contact, such as branches adjoining a solid surface - for instance, reoccurring strikes from wind or impact from a fall; both options are rare and neither justify any form of tree removal or harbour inherent risk.
Roots by nature - once in contact with anything solid, will naturally redirect themselves to the path of least resistance, thereby causing no damage. Exceptions to this are when limited space is available near a structure, and trunks expanding may provide enough force to displace or shift heavy structures.
Indirect damage is defined as the effect of a tree on soil moisture levels of a substrate prone to reduction and growth. Other indications are dehydration through the transpiration of leaves absorbing moisture from the surface and less impactfully through rainfall being obstructed by the crown.
If obvious damage has presented itself, it is advised you contact local arborist services or professional tree service specialists for analysis or structural inspection.
Arboricultural Factors that Determine the Likelihood of Tree-Related Damage
1. Variation amongst tree species
Recognising a tree correctly is foundational to the evaluation of its (potential) moisture level and capacity. It is important to differentiate and understand the genus and species.
Most reference or data tables will refer only to the genus, such as 'beech' or 'willow'; it is important to note the large differentiation of species within a genus - there are more than two thousand contrasting species within the pine family, varying in growth, size and their conditions.
Defining a tree under 'beech' or 'pine' is unintelligible without qualification to elucidate it. In tandem with species needing reference, so does the cultivar. For example, there are a plethora of Lawson cypress cultivars with a multitude of variations in size; 'Triumph of Boskoop' can exceed 25m while a 'Pembury Blue' likely won't exceed 3m. The importance of classification gives insight into why tree removal shouldn't be based simply on that a tree is a 'cypress' as the tree may be assuredly innocuous.
2. Intraspecific differentials
The differences between any two species are rarely accounted for, and information is scarce. Even with genetic clones, there can be a multitude of differences within a species of tree.
While two trees may be nominally identical, their physiologies and characteristics may be drastically different - two horse chestnuts, while nominally the same, can have different moisture patterns or rates. Soil moisture consistently fluctuates between 4m and 1m(13feet and 3feet) of depth between four closely sized horse chestnuts naturally planted and grown in London clay.
Using this information, P.G Biddle suggests that leaving a tree and its roots undisturbed may be the best course of action to prevent building damage.
3. Phenotypic variation
In short, Phenotypic variation is a foundational determinant of soil moisture abstraction capacity. On different sites, even genetically identical trees (identical clonal origin) will present different patterns of soil drying; this proves that environmental or local factors have a huge impact on a tree's growth rate and pattern.
While a silver birch may struggle on a shadier, poorly drained site, an identical clone of the same silver birch will thrive in a well-drained open site and provide significantly different growth patterns. This information is the basis behind the reasoning that a considerably smaller than its natural size but a mature tree could not need to be removed.
Moisture uptake and rates of growth are determined by rootstock, not the scion.
This is distinctly underlined where scions taken from an identical apple tree could be grafted onto a multitude of varying rootstocks that will determine if a tree stays a small fastigiate tree growing to 2m x 0.5 or 9m x 9m.
Knowing that roots of an identical species will graft; it is to be assumed that there is a possibility, theoretically, of a property to fall within the root zone of influence of a tree whose roots couldn't extend as far as the property if there is a closer tree of an identical species and root graft has occurred.
5. Vitality concerning moisture abstraction capacity
Vitality concerning moisture abstraction capacity refers to how vigorous a specific tree is; rather than the species in general. For instance, a specific Sycamore could be suppressed, diseased, old or lack vitality; however, Sycamore's by nature are a vigorous species. There may be a very minuscule impact on soil moisture levels from trees of lower quality vitality, regardless of the vigour of the species or water demand classification (NHBC).
When trying to establish the stage and health of development of a tree, you should look out for certain characteristics such as; extension growth of terminal and lateral buds, crown shape and apical dominance.
Characteristics, such as competition, poor health, climatic conditions, poor tree-work or inappropriate ground, are all likely results from low vitality. From this, we can gather that assessment of the crown is more useful than the tree's height. While most recent formulas utilise the ultimate tree height as a key factor within the equation, a tree may have a tall crown but an exceptionally low rate of root distribution and moisture abstraction due to the total leaf area being relatively small.
6. Competition concerning moisture abstraction capacity
Trees adapt their growth rates based on their environmental factors and survival; this means that groups of trees won't bear more influence on a property than a single tree would or if a tree is too close to another. While trees grow closely within proximity of each other, trees adapt to distribute resources between each other.
An arborist will understand that trees growing slower due to competition is typical, but the competition itself shouldn't affect or bear more influence on a property. Modified growth rates indicate a clear impact on moisture uptake and transpiration rates - if a group of four trees grew tightly together near a wall, the zone of influence would be localised, but the wall is still unaffected.
7. Significance of Crown Type
Through a process of transpiration via the total leaf area, tree abstract moisture rates can be determined. This principle states that the healthier and larger the tree's crown is, the better the moisture abstraction capacity.
Tree canopies are also relevant in assessing or aggravating any dehydration process as they hinder rainfall from hitting the surface; 25% of rainfall is estimated to be prevented by canopies and the crown, 33.33% of this evaporates in the tree.
In most cases, such as with Cypresses, any damage to the property or yard is usually due to rainfall interception and not the Cypress itself or its high water demand.
Shrubs don't get as much attention as trees and are often overlooked because of this. However, they have very similar patterns when it comes to root development.
A multitude of shrubs are capable of growing intimidating plants even to the scale of most small trees. Some examples of shrubs capable of this feat are buddleja, elderberry, laurel, cotoneaster, ivy, pyracantha and wisteria, and all have the potential for major moisture abstraction.
More important than their moisture abstraction capacity is their associated relevant characteristics:
Shrubs are often grown adjacent to each other and develop dense clusters of foliage; upon an investigation of the ground below, often you'll find high desiccated ground during winter periods where the ground could be saturated.
Shrubs are commonly grown with close distance to buildings and walls with the intent to soften the structure. Due to this, drastic localised drying is possible, and roots will likely trespass upon foundations.
Shrubs are often deemed innocuous to an extent and will often grow into large specimens due to being overlooked. This factor leads to wisteria or mature ivy commonly covering houses or entire walls.
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