242 



HINTS AND NOTES 



called vermin by the game-keeper are especially 

 at home. 



It is probable that a certain amount of dis- 

 persal of plants is effected by these animals, 

 the pads of the fox being often filled with clay 

 in which seeds maybe carried for long distances. 

 Upon the spines of the hedgehog large fruits 

 such as crabs may be transfixed, and burs may 

 stick to them. 



Birds, especially in woodlands, act as carriers 

 of seeds from one place to another. The hard 

 seeds of fruits may be dropped after the soft 

 exterior has been eaten. In the same way 

 squirrels may disperse nuts, storing them and 

 forgetting them. Woodpeckers and titmice 

 are factors in a woodland to be considered, 

 because they aid the destruction in time of the 

 trunks, which they riddle with holes and expose 

 to air and rain, causing them to rot. The 

 innumerable interactions between plants and 

 animals are full of material for study. 



Ancient Woodlands. The antiquity of the 

 woods and forests in this country is undoubted, 

 but as yet little definite information is avail- 

 able, from the absence of any clear evidence 

 earlier than the deposits that just precede the 

 Ice Age or the Cromer Forest bed. In addi- 

 tion to the numerous other plants, some, as 

 Trapa natans (Water Chestnut), denoting a 

 warmer climate, there were remains of the fol- 

 lowing frees: Elm, Oak, Beech, Hazel (rare), 

 Alder, White Birch, and three species of Wil- 

 low. These indicate the same type of wood- 

 land that is met with in this country to-day. 

 If one were to examine the flora of the earlier 

 Oligocene or Eocene one would find that the 

 climate was still warmer, and in the Bovey 

 Tracey beds the giant or mammoth tree type 

 of California, Cinnamons, Evergreen Oak, 

 Fig, Laurel, and in the Bournemouth beds of 

 the same age, Eucalyptus, Araucaria, Sequoia, 

 riatanns, are found, indicating as warm a 

 climate. 



Between these beds and the Cromer Forest 

 bed we have no very clear connection, but Oak, 

 Elm, and Poplar of allied species occur. The 

 submerged forests around the coast belong to 

 a later period than the Cromer Forest bed, and 

 contain the present-day trees. 



The Peat beds of Scotland have two forest 

 beds, the lower containing largely White Birch, 

 whilst the upper contains Pine, and these lie 

 over Glacial beds. In Norway there is a third 

 forest bed of Spruce. Thus, whilst we are 

 largely foiled by the influence of the Ice Age 

 in determining the area and age of ancient 

 woodlands, there are certain data which indi- 

 cate that they are Preglacial. 



Tree Zones. The influence of altitude upon 

 plants varies in degree. The tree type is 



especially affected by altitude, and in a corre- 

 sponding manner by latitude or climate. In 

 the tropics the belts as the loftier mountains 

 are ascended correspond with those which are 

 observed as one travels from the Equator to 

 tlie poles. Thus at the Equator there are wet 

 jungles of palms and bananas, followed by 

 Savannahs, 10 degrees north to 20 degrees. 

 Between 20 degrees and 30 degrees the main 

 deserts are met with. Then come the Steppes 

 and woods, made up of evergreen trees be- 

 tween 30 degrees and 45 degrees. 



The large deciduous forests range between 

 45 degrees and 55 degrees, and it is in this 

 zone mainly, the cold temperature zone, that 

 the British Isles are included. Northward 

 from 55 degrees to 65 degrees come the Pine 

 forests of Norway and countries of the same 

 latitudes, as Canada in North America. The 

 frozen Tundras, all but treeless, come between 

 5 degrees and 75 degrees. The everlasting 

 snow lies north of this, and beyond the snow- 

 line only mosses and lichens will flourish as a 

 whole. 



In ascending a tropical mountain there are 

 from sea-level to 4000 ft. tropical forests, from 

 this point to 8000 ft. sub-tropical forests, and 

 upward to 9500 ft. temperate deciduous forests. 

 A zone of conifers comes next between 9500 

 and 11,500, alpine shrubs between 11,500 and 

 13,300, alpine herbs up to the snowline, and 

 above it mosses and lichens. 



Woodland Habitats and Associations.- Habi- 

 tats in general may be wet or dry, rocky or 

 not, upland or lowland. The wettest habitats 

 (especially E. Anglia) are afforded by the 

 Alder-Willow associations, where the scrub and 

 ground flora is made up of such plants as 

 Guelder Rose, Currant, Gooseberry, Meadow- 

 sweet, Yellow Flag, Reed, &c., Bitter-cress, 

 Kingcup, Figwort, Great Hairy Willow-herb, 

 Tussock Grass, &c. The tree types are scat- 

 tered, and the ground itself is open, allowing 

 such large herbaceous plants to thrive. 



On clays and loams, sandy and siliceous 

 soils, the trees are Oak, pedunculate and 

 sessile, Birch, with other trees. The scrub 

 and ground flora are very variable. The 

 woodland may be close or open. On clays and 

 loams the ground flora is largely gregarious, 

 e.g. Bluebell, Bracken. On sandy soils more 

 often there is a good deal of bare rock surface 

 with deep soil elsewhere, giving a variety of 

 habitats. The same applies to a Birch wood. 

 Here also there are wide associations of grasses, 

 such as Heath Hair Grass, Matweed, &c., and 

 the heaths also form wide gregarious associa- 

 tions. These habitats are largely upland, 

 whilst the oak-woods are mainly lowland, the 

 sessile Oak not growing above 1500 ft. as a 



