High winds and trees.

The UK has recently experienced another storm, characterised by strong winds and heavy rainfall, which can be detrimental to soil and trees. Saturated ground may cause tree roots to loosen, and when combined with strong winds, trees can start to sway and potentially topple. Tragically, this can result in injuries or even fatalities, as well as property damage. This often leads to public outcry against the council for not ensuring tree safety. However, it's worth noting that council tree officers, if present, are typically overstretched and manage multiple responsibilities simultaneously. While they may pass the same trees daily, effectively conducting subconscious tree surveys, it's impossible to catch every potential hazard.

Regarding the prevailing wind direction in the UK, it predominantly originates from the South West. This historical detail sheds light on the urban planning of the 19th and 20th centuries, where affluent businessmen constructed their grand homes in the southern and southwestern parts of cities to avoid the smog and odours carried by the wind from the more densely populated and poorer areas. 

Trees display similar behaviours. As mentioned earlier, the prevailing winds come from the South West. When you next venture into the woodlands or observe a lone tree in the countryside, take the time to study its shape. It may act as a navigational tool (which I'll cover more in a future blog), but the crucial point to examine is the base of the trunk, near the buttress roots. You'll likely observe that the buttress is more developed on the side facing the dominant wind. This isn't a defect in the tree, but rather a defence strategy to remain standing. The wind typically exerts pressure on the South West side of the tree, altering the root structure to become more elongated to withstand the additional stress. Consequently, the root flare becomes more noticeable, and as you circle the tree's base, you'll see that the trunk is thinnest when viewed in alignment with the prevailing wind direction.

During autumn and winter, the likelihood of high winds and rain increases. When strong winds shift and originate from the North, for instance, trees may struggle to withstand this unusual direction. Lacking developed root flare, they are more susceptible to being 'wind-thrown'. This is why trees are more prone to being toppled by the wind in winter. Moreover, many urban trees are planted in inappropriate locations, such as grass verges, where their roots cannot properly develop to support the tree due to lack of space. Additionally, when street parking is scarce, motorists often park on these grass verges, further exacerbating the issue. This constant weight of the cars wheels compacts the soil around the roots of the trees, which not only damages the roots but compacts the soil so much that the fine roots can't penetrate the soil to look for nutrients. 

Urban trees are often damaged by strimmers, vehicles, and people who strip the bark, which allows fungal pathogens to invade. This stress leads to root rot, the emergence of fungal fruiting bodies, and eventually, the tree succumbs. In the next strong wind, the weakened tree may topple, potentially causing fatalities. Subsequently, it becomes a news story, with many speculating on the cause of its fall. The roots may appear soft and spongy or be absent on the side opposite to where it fell; the bark shows signs of damage. Yet, it often seems that the council is blamed, as their staff are unable to see and assess the underground damage to the roots. 

The next time you witness an urban tree falling, pause to reflect on the reasons behind its collapse. Investigate and scrutinise the tree's state before jumping to conclusions about predictability. Consider what external elements might have contributed to its fall. Observe the tree's surroundings, note the parking of cars, and assess whether the soil is compacted or bears significant ruts from vehicle tyres. All the aforementioned factors collectively create the perfect conditions that can lead to the tree's demise.  

Trees are vital to our environment, yet they seem to often go unnoticed until they fall, cause injury, damage property or block the road and stop you from going on that all important journey.