WOODLAND ECOSYSTEM - TAI PO KAU NATURE RESERVE FIELD STUDY

WOODLAND ECOSYSTEM - TAI PO KAU NATURE RESERVE FIELD STUDY

4C Cheung Tsz Ching (11)

4C Li Huan Huan (22)

4C Tai Mung Wan (27)

HISTORY AND INTRODUCTION OF TAI PO KAU NATURE RESERVE Tai Po Kau Nature Reserve, located in the Tai Po Kau

Special Area. It has been well known among all the people who are interested in nature. It was originally

called the Tai Po Kau Plantation, there are 440 hectares of forest on the steep catchment area of the stream near the car park area at the entry of the country park. The height extends from 50 metres to 650 metres at the top of Grassy hill ( Tso Shan ) .

WEATHER CONDITION ON 6/3/2010

The temperature range is about 20-22 ℃. Sometimes, there were sunshine but with a cloudy sky.

Relationship between different tree layers and relative humidity

Water, or moisture, is the most important factor in a habitat. It carries nutrient to the vegetation that favors the process of photosynthesis.     Due to much rainfall, vegetation amount in Tai Po Kau is very much. It shows that the weather is wet enough for vegetation growth. As the tall trees need much water that works as the raw material for photosynthesis, the relative humidity will be higher.

Besides, tall trees (Canopy layer and emergent layer) block lots of sunlight, reduce level of evaporation, so, the surrounding air contains relatively more moisture, and relative humidity is high.

Short trees (ground layer and shrub layer) also need water to grow, most of the sunlight absorbs most of the sunlight, and so, short trees and the surrounding air may be wet as the evapotranspiration rate is low. The relative humidity may be higher than the tall trees layer.

THE AMOUNT OF VEGETATION COVER AFFECTING STEMFLOW AND THE QUALITY OF THE SOIL The branches of the trees intercept the large

amount of rainfall, most of the water runs along the branches and reaches the ground.

      Rainfall affect soil formation so much. The rapid of stemflow will cause leaching. Heavy rainfall causes a downward movement of water and the soluble materials in the soil, the soluble materials may be slash away by the rainwater. There is a strong downward movement of bases and silica that is decilication. Without silicate colloids, the soil is firm and porous rather than sticky and plastic, transmitting water easily, the horizons are not distinctive although lower layers tend to be darker in color due to the accumulation of bases and colloids.

In conclusion, stemflow may destroy the structure of the soil and the nutrient of the soil may be loss by the slash of the rainwater and leaching.

SPECIES FOUND IN TAI PO KAU NATURE RESERVE

The dominant tree was Chinese Red Pine ( Pinus massoniana ) and because of that the area has come to be known locally as Tsung Tsai Yuen, meaning Pine Garden. More recently, small areas of Camphor Tree, China Fir, Acacia and Paper-bark Tree have been planted

There are also many interesting native species, such as the Litsea, Giant Bean and Sweet Gum. As you walk along the quiet paths you find stretches of ground carpeted with large, brown leaves. These are from the tree called Castanopsis fissa, a good timber tree formerly much used by the Chinese in making agricultural implements such as the primitive wooden plough. Of all the special areas in Hong Kong, this one is probably the richest in variety of native species of trees.

ADVANTAGES FOR PLANTS TO BE EPIPHYTES

Epiphytes is a kind of herbs that grow in crevices of the larger trees, without roots, epiphytes cannot uptake nutrient from the soil but by growing in crevices of the larger trees in a network-like shape, letters trapped by the epiphytes then become the nutrient for them

 Epiphytes absorb more sunlight and rainwater than other short plants because it crevices the larger trees so they can get to a higher place which can receive more sunlight and rainfall.

DIFFERENCE BETWEEN EPIPHYTES AND PARASITIES

Parasities is a kind of climbers which also grow in crevices of the larger trees. But they are also nourished by host tress, some have aerial roots in which falling leaves may be trapped and then provide the plants with nutrients.

   Parasities take nutrient from the host trees, sometimes, or eventually, the host trees may die as the parasities uptake most of their nutrient.

Epiphytes just grow in crevice of the larger trees but do not take any nutrient from the trees. So, they are not harmful for the trees and will not affect the lives of the trees.

THE DIFFERENCES BETWEEN THE CROWNS OF EMERGENT LAYER AND THOSE OF THE LOWER LAYER

As  this is a Sub Tropical Rain Forest, it made up of a range of codominant species. As they want to fight for the sunlight, the main canopy is the emergent layer. They are the main canopy, most of them have umbrella-shaped crowns in order to increase the surface area to obtain maximum sunlight.

Therefore they can intercept most of the rainfall, and obtain most of the insolation. And the drip tips of the leaves allow the moisture from the frequent rains to be shed to the lower layer. And there is some buttress root or stilt root, it provide added stability to very tall trees.

The appearance of buttress root

And the continuous canopy. Most of them are 15 to 30m and with long tapering crowns. About half are usually sapling of the larger trees. From a continuous canopy which absorbs more than 70% of the ligh and intercept 80% of rainfall. They shade the underlying species, but they protect the soil from erosion.

-The lower layer of the canopy.

The shorter trees under the following canopy only about 10m. It have crowns that are narrow in proportion to sunlight, an adaptation that enables them to take maximum advantages of such light as penetrates the canopy. In the TRF there are not many shorter trees. As the result of the competition for sunlight, it is discontinuous and becoming dense only where there are breaks in the canopy. They included herbs, such as ferns. A considerable proportion of bare ground and little undergrowth because there are less than 5% of insolation to forest floor.

The lowest layer grow in the breaks in canopy. They are usually small in size.

THE FUNCTIONS PERFORMED BY BUTTRESS ROOT

According to the photo we can see that the spur-like swellings at the base of the tree trunk are known as buttresses. The buttress provide support of the tree and it increase the stability of big trees. It can grow much future away from the main stem. In a nut shell, this is a structural adaptation of the trees.

THE WAYS OF THE PLANTS CLIMB

The climbing plants from by the wind from tree to tree from the forest floor, beginning their growth in shaded conditions and forming branches, when they reach the upper layers and obtain sufficient light.

They growth along the stem of the host tree and then climb up to the top in order to obtain sufficient sunlight for their growth. They can climb up to the upper part or even the top of the host tree.

THE IMPORTANCE OF LITTER TO SOIL QUALITY

In the photo there is a lot of l litter on the floor it act as a important role in the soil quality. Because it provide a lot of nutrient to the soil. The rapid decay of the leaf litter and recycling of nutrient. They are produce by coniferous evergreen trees and healthland.

After they decompose they become humus finally, and humus is the major source of nutrients and it combines with clays to form clay-humus complex which is very important for a fertile soil as it provides it with a high water-and nutrient-holding capacity.

 Also humus act as a cement, binding he soil particles together and thus reduces the risk of erosion by improving cohesion

The humus is decomposed by bacteria, earthworms and fungi. The present of humus tends to give the soil a brown or black colour.

Present of Fungi and the dark brown soil

SOME PHOTO