MMM #8: The Giant & The Waterfall
This is the 8th of a 17-cache series which will take you on a wonderful 6km looping trail up the deep Morton valley through Sunnydale and The Glen passing historical farm and residential buildings, industrial ruins, mill ponds and weirs, rich deciduous and pine woodlands, a reservoir, waterfall, low moorland, farm fields and then back down an old track and flower-festooned path into the village.
The cache, a camo-topped 35mm film pot, is hidden near a lovely, deeply shaded small waterfall.
Directions: from #7 return to the path and continue through the gap in the wall, across a restored footbridge over a small beck draining down from a spring north of Glen Farm. Continue to the cache location near the footbridge over Sweet Well Dyke - which flows into Sunnydale Reservoir and is one of the 3 main streams which unify to form Morton Beck further down the valley.
The cache is overlooked by a mighty beech tree with extraordinary exposed roots anchoring it to its rocky base. Beech trees have shallow, even superficial, roots systems with large roots spreading out in all directions. European beech forms ectomycorrhizas (symbiotic relationships) with a range of fungi which are important in enhancing uptake of water and nutrients from the soil.
Tree roots do not generally occur in great amounts at any significant depth. Most are located in the top 1 - 2m of the soil - trees tend to have shallow but extensive root systems.
The spread of lateral roots can be as great as the spread of the canopy or crown, or even beyond in some cases. One study showed that the root spread of poplar was greater than three times the crown radius. Root systems such as this are sometimes referred to as extensive systems.
An intensive root system is one that is confined to a smaller soil volume, relying on shorter laterals, which have numerous fine endings. Such a system may be seen in beech (Fagus sylvatica). As a result, beech tends to suffer more than most tree species in droughts, although it can penetrate to great depths of some soils.
Surveys of trees blown over in storms shows that only 2 - 3% had distinct tap roots. Oak, pine and silver fir are amongst those that may have persistent tap roots. Other species have what are termed 'heart root systems' where larger and smaller roots penetrate the soil diagonally from the main trunk. Trees such as larch, lime and birch can fall into this category.
A surface root system is one where the roots tend to run horizontally just below the soil surface, with some roots descending deeper and vertically into the soil. Ash, aspen and Norway spruce can provide examples of this.
However, there is no clear or simple classification of root systems. Much depends on local geology, soil type, climate, drainage etc. So, for example, water logging of the soil will limit gas exchange, which will affect the oxygen the root can get for respiration – which generates energy for growth and the take up of minerals. When the oxygen level in the soil falls, root growth is reduced or stopped completely. The availability of oxygen can also be reduced by compaction of the soil.
See here for a fascinating 2005 paper by the Forestry Commission on tree roots - types, depth and relationship with soil based on examination of the root plates of blown-over trees - 0f which there are many more after last winter's storms - including several along this route.
Some more QI facts on tree roots . . .
Trees - as with all plants - 'talk' to each other and a wood or forest can be seen as a super-organism composed of numerous individuals. All the trees in every forest that is not too damaged, are connected to each other through underground fungal networks. They share water and nutrients through these mycorrhizal networks, and also use them to communicate. They send distress signals about drought and disease, for example, or insect attacks, and other trees alter their behaviour when they receive these messages.
The fine, hairlike root tips of trees join together with microscopic fungal filaments to form the basic links of the network, which appears to operate as a symbiotic relationship between trees and fungi, or perhaps an economic exchange. As a kind of fee for services, the fungi consume about 30% of the sugar that trees photosynthesize from sunlight. The sugar is what fuels the fungi, as they scavenge the soil for nitrogen, phosphorus and other mineral nutrients, which are then absorbed and consumed by the trees.
For young saplings in a deeply shaded part of the forest, the network is literally a lifeline. Lacking the sunlight to photosynthesize, they survive because big trees, including their parents, pump sugar into their roots through the network.
