Trees and Modifying the Environment
In this piece of work the main hypothesis I am studying is "Do trees
modify their environment", this basically is asking Do tree change
I have simplified the main hypothesis into three smaller hypotheses,
to make it easier for me to explain my prediction and results.
The three hypotheses
1. Where there are trees
there will be less light, less soil
moisture, the temperature will be lower, there will be less plants
growing on the ground, and the soil ph will be more acidic, than
an area where there are no trees.
2. Where there are deciduous trees there will be less light, more
soil moisture, the temperature will be lower, there will be less
ground cover, and the soil will be less acidic, than an area where
there are coniferous trees.
3. Where there are young trees there will be more light, the
temperature will be higher, the soil will be more moist, there
will be more plants growing on the ground, and the soil ph will be
less acidic, than an area where there are old trees.
[IMAGE]I visited Bishops wood to obtain my results. Bishops is a
country park, owned by the council. It lies south of river Colne, west
of Northwood and abuts the country boundary. The area has a distinct
sloping, and it has steep slopes that tumble towards the river Colne.
Tall hedgerows, trees and fences surround the park. Most of the land
use is recreational, there are three golf courses, some of the land is
used for horse grazing and the rest of the land is used for forestry.
I maintained my results in the forest are of the park. The park
harbours a lot of wildlife, and also has different trees such as oak
and beach trees (deciduous trees); the park also has conifer trees
(coniferous trees) growing.
To maintain our results, we went to a deciduous and coniferous
woodland, we also experimented across a path.
We experimented for a range of things, using a range of different
The first thing we looked at was ground cover, we done this by, laying
a twelve-meter transect (measuring tape) across the ground, and then
we placed a half meter quadrant at 0m, 4m, 8m and 12m. We estimated
the ground cover in percentage; we looked for leaf litter, grass, moss
Another member of my group tested for soil PH, he done this by putting
soil into a tube, next he added Barium sulphate, distilled water and
universal indicator; he shook the solution and waited for it to
settle, then he compared it against a PH identification chart to find
out the soil ph.
After that we checked the soil moisture, we done this by placing the
soil moisture meter probe in the ground, and this gave us a reading of
0 - 10. Light readings where taken in a similar way, it was done by
holding the light meter probe in the air, and seconds later we wear
given a reading in percentage. Afterwards my group looked at the age
of trees, we done that by measuring the circumference of the tree, 1.5
meters from the ground. The last thing we tested for was temperature;
this was simply done by holding a thermometer in the air, we recorded
our results in degrees centigrade.
My first hypothesis is; where there are trees there will be less
light, less soil moisture, the temperature will be lower, there will
be less plants growing on the ground, and the soil ph will be more
acidic, than an area where there are no trees.
The transect I am going to describe is the one I laid in the
Along this transect I found leaf litter in all four quadrants at a
total of 255%, the second most dominant element found again in all
four quadrants was twigs at a total of 140%. I also found 32% moss and
35% soil in two of four quadrants. The least element was found in all
four quadrants at 25%. I also found the following results; light -74%,
temperature -10.2 degrees centigrade, soil moisture -3, soil ph -5
(acidic) and 34% plants growing.
The second transect I am going to describe is the one I laid across a
path in a coniferous woodland. I received the following results; 342%
leaf litter was found in all four quadrants. 65% twigs found in all
four quadrants. 15% Soil was found in the 12m quadrants, and 7% acorns
were found in the 4m and 8m quadrant. Also 4% nettles, 4% moss and 3%
stones were the least amount of elements found in this quadrant. Other
things were tested in this quadrant; I managed to obtain the following
results; light -81%, temperature -9.6 degrees, soil moisture -5, soil
ph -5 (acidic) and 8% ground cover.
In my first hypotheses I predicted there to be less light where there
are trees, than an area where there aren't any trees. I was correct
light (74%) was less in the wood because the canopy was blocking the
light, and light (81%) was more in the path because there is no canopy
to absorb the sunlight.
I thought soil moisture would be less in a wood than a path, my
results show I was correct, the woodland soil moisture was 3, which
was less moist, than the path soil moisture at 5, this was due to
higher temperatures, which make the water evaporate, another reason is
the trees could have absorbed most of the water through their roots in
Next I predicted temperatures would be lower in the wood, than a path.
My results show me temperature in the wood was 10.42%, this is higher
than the temperature recorded at the path, that was 9.6%, these
results were unusual and didn't match my prediction, this could be
because the temperature was recorded at different times of the day or
the trees may have been over shadowing the path. Temperature across
the path was recorded in the morning and the temperature in the
woodland was recorded later on about midday, this is why the
temperature was different.
I predicted ground cover to be more in a wood than a path; my results
show plants growing in the woodland is 34%, and ground cover in the
path is 8%, so therefore my prediction was right ground cover was more
because people walking along the path, kill vegetation growing by
trampling on them; this results to soil erosion.
The lasts prediction made in the first hypothesis was; soil ph will be
more acidic in a wood than a path, my results show both were equally
acidic at 5ph. Reason being, pine needles from pine trees are acidic
so when they decompose they make the soil acidic.
My second hypothesis is; where there are deciduous trees there will be
more light, less soil moisture, the temperature will be higher, there
will be more ground cover, and the soil will be more acidic, than an
area where there are coniferous trees.
I am going to describe the transect I laid in the deciduous woodland.
This transect showed a high amount of leaf litter at 360%, the second
most dominant element found was 47% twigs and the least element found
was 4% nettles and 1% earth.
Other results I obtained were light - 82%, temperature - 10.9 degrees,
soil moisture - 1.2, soil ph - 6ph (acidic) and ground cover was 4%.
The second transect, which is going to help me prove my hypotheses is
the one I laid in the coniferous woodland. In analysing my data I
found that the leaf litter was 95% less than the leaf litter in the
deciduous woodland. The second most dominant feature in this transect,
was 140% twigs, found in all four quadrants. 32% moss was found in the
0m and 12m quadrants, also 35% soil was found in 2 of 4 quadrants. The
least element found was 25% acorns. Moss and acorns weren't found in
the deciduous woodland however nettles were found in the deciduous
woodland but were not found in the coniferous.
The following results were also found; light - 74%, which is 8% lower
than the light result found in the deciduous woodland. Temperature -
10.42, soil moisture was 2.5 times higher in the coniferous wood than
the deciduous woodland. Soil PH - 5ph (acidic), and ground cover was
In this second hypothesis I expected the deciduous wood to be lighter,
hotter and drier than a coniferous wood. I also expected the soil to
be more acidic, and ground cover would be more there. My transects
show I was partly correct as the light in the coniferous wood was 8%
lower, than the deciduous wood. So therefore my prediction was right,
because my results show that the deciduous wood was lighter. A
possible reason could be that the canopy is smaller, due to the fact
that the trees are planted randomly, this allows more light to reach
the ground. I found out the deciduous wood was hotter than the
coniferous wood, due to the fact that the temperatures were recorded
at two different stages of the day (morning for coniferous, and
afternoon for the deciduous), another reason could be threes are
planted randomly, making the canopy smaller and allowing more sunlight
to reach the ground and turn to heat energy, which makes the
surroundings hotter, this that my prediction was right.
The deciduous wood was drier than the coniferous wood; because the
deciduous wood is hotter so therefore more water evaporates leaving
the soil less damp. Looking at my results I noticed that the soil is
more acidic in the deciduous wood; because it is so hotter in a
deciduous wood compared to a coniferous wood, this causes more leaf
litter to decay, and the decaying of leaf litter results to acidic
soil; so my prediction was right. Finally I found there were less
plants growing in the deciduous wood than a coniferous wood, this is a
result of the fact that not the soil was dry which means plants didn't
have enough water to follow the process of photosynthesis.
My third and final hypotheses is; where there are young trees there
will be more light, the temperature will be higher, the soil will be
more moist, there will be more plants growing on the ground, and the
soil ph will be less acidic, than an area where there are old trees.
Younger (coniferous wood) (8m quadrant).
Older (Deciduous wood) (8m quadrant).
I will explain what I found in the transect I laid in the coniferous
wood, though I am only going to describe what I found in the 8m
quadrant. Firstly the 8m quadrant shows me the highest element found
was twigs -65%, the second highest element found was leaf litter-35%,
the least elements found was Pine cone -10% and Soil -5%. I also
obtained the following results, light -74%, temperature - 10.42
degrees, soil moisture - 3, soil ph - 5 (acidic), and plants growing -
The second transect I am going to describe is the one I laid in the
deciduous wood, but again I am only going to describe what was found
in the 8m transect. Only two elements were found in the 8m quadrant;
the two elements were, leaf litter -95% and twigs -12%. I also
received the following results; light - 82%, temperature - 10.9
degrees, soil moisture - 1.2, soil ph - 6, and plants growing - 4%.
I have recorded additional results, which are relevant in proving this
hypothesis. I recorded the ages of 20 trees in total, 10 trees were
coniferous trees and the other 10 trees were deciduous trees. For a
coniferous tree I divided the size (cm) by 3.13, this gave me the age
of the tree. I used the same method to work out the age of a deciduous
tree but divided the size (cm) by 2.50. I then worked out the average
age of both coniferous and deciduous trees, this gave me the following
answers, average age of coniferous trees is - 57.8 years, and the
average age of deciduous trees is - 87.2 years; so therefore the
coniferous woodland is younger than the deciduous woodland.
In this final hypothesis I expected to find the younger woodland
(coniferous wood) to be lighter, hotter and wetter. I also expected
the younger woodland (coniferous wood) to have less acidic soil, and
more plants growing on the ground, compared to the older woodland
My results show me that I was partly right; I found the younger wood
(light - 74%) was not lighter than the older wood (light- 82%); there
is difference of 8%. This was unusual to find as I thought the younger
wood will have more light because its canopy will be small, so it
absorbs less sunlight, this enable more sunlight to reach the ground.
However my results prove me wrong, a possible reason for this could be
the results were recorded at two different time of the day (am, pm).
I also predicted the younger wood to be hotter than the older wood; my
results show me I was wrong. The reason for the younger wood being
hotter than the older wood, could be, the temperature was recorded at
two different times of the day (am, pm), this can also depend on the
weather, when I recorded the temperature for the younger wood it was
cloudy, and when I recorded the temperature for the older wood it was
I found the younger wood was wetter, just as I predicted. This could
be because the younger wood (10.42 degrees) temperature was lower than
the older wood (10.9 degrees), and low temperature results to less
evaporation, which leaves the soil damp. This is why the soil was
wetter in the younger wood.
The soil was more acidic in the older wood, because the bigger canopy
prevents sunlight reaching lower leaves, lack of sunlight means leaves
aren't able to perform photosynthesis, causing leaves to die and
become leaf litter. As leaf litter decomposes, it increases ph of the
The younger wood had more plants growing, as I predicted. More plants
were growing because the soil was more moist (3); this provided the
plants with water, and nutrient to grow. Also the younger wood has a
smaller canopy, so more sunlight reaches the ground, this helps plants
to photosynthesise and grow.
Looking at what I found, I conclude that trees do modify their
by if there's more trees e.g. woodland, there is less
light as most of the sunlight is blocked by the canopy. This means
that the soil will be more moist as not enough sunlight reaches the
ground therefore not much evaporation occurs. Also not much plant life
exists due to the fact of not enough sunlight.
Transect one Coniferous wood: -
Transect two across path in coniferous wood: -
Transect three deciduous wood: -
Transect four across path in deciduous wood: -