Sunday October 13
Soils and habitat
The big categories of soils are limestones (alkaline, pH> 7) and clay soils (acid, PH <7), which come from the decomposing rock: the Provençal mountains are calcareous, while the Hercynian massifs (Massif central, Armorican Massif) are sour. The peaty soil is typically sour (and it is suitable for plants " acidophiles ", rhododendron, azaleas).
Most trees prefer clay soils, therefore sour, which keep the water, while limestones, more permeable, dry out fast and warm up. The trees which do not support limestones are "calcifuge" (The word is derived from a latin word meaning 'to flee from chalk'). Trees preferring limestones are rarer: they are said "calcicole". See the list
To feed, trees also scoop out some nitrate of the soil: they are nitrophile. But some pioneer species accept poor soils, because they adapted a technology to extract the nitrogen from air. For this, they join mushrooms fixed on their roots (alder) or bacteria (Rhizobium of the family of leguminous plants).
Humidity and drought are also habitat distinctives: the trees which grow preferably in humid zones are said hygrophilic. Those which fit to drought are xerophilous. See the list
Other necessary factor (in photosynthesis): sunny position. Some species need light: they are heliophilous. Those which support the shade are shade plants.
The appearance of forests is the logical culmination of a natural process: a moor or an uncultivated abandoned agricultural ground (ground a priori richer than the moor unless it was exhausted by cultures) is colonized by so called pionee species, few demanding as soil but demanding in light: Scotch Pine, Birch. The fall of leaves and of pine needles maintains a humus (rather acid in the case of the pine), which can receive shade species (beech, fir). These are going to rise so as to pick up the light, making shadow to the young shoots of the previous species, which turn white and cease renewing.
Finally, some species fit in seaside, what does not prevent them from losing its shape in the wind, and from developing less on the side exposed to the wind. Others support altitude.
- Trees of full light
- Trees tolerating shade
- Trees tolerating the sea air (halophilous)
Salt air is dangerous, it burns leaves, and at times far inside lands when the wind blows from the sea. One saw the foliage of trees burnt at 3 km far from the shore. - Deciduous trees
- Conifers
- Trees tolerating altitude
- Deciduous trees
Whitebeam, Sorbus aria
Whitish alder, Alnus incana
Birches, Betula
Spanish chestnut, Castanea sativa
English Oak, Quercus pedonculata
Norway Maple, Acer platanoides
Sycamore, Acer pseudoplatanus
Beech, Fagus sylvatica
Common Holly, Ilex aquifolium
Smoothleaf Elm, Ulmus campestris
Elm of mountain, Ulmus montana
Poplars, Populus
Locust tree, Robinia pseudoacacia
Willows, Salix
Rowans, Sorbus aucuparia - Conifers : most support altitude.
Araucaria of Chile, Araucaria araucana
Cedars
Cypress of the Arizona, Cupressus arizonica
Norway Spruces
Common Juniper, Juniperus communis (dwarf in altitude)
Larches
most Pines (except the Maritime pine)
most Firs, of which the Fir pectinate, Abies alba
Douglasfir, Pseudohemlock douglasii
Giant, Sequoiadendron giganteum Sequoia
Western red cedar, Arborvitae plicata
Hemlocks
The growth of a tree in undergrowth is considerably decelerated. If shade is dense, the more difficult is growing, often without blossoming nor fructification. Here is the list of trees requiring a full light : click here.
Few trees search shade, because by definition, light is their source of growth. However some conifers demand covered setting at the beginning of their installation:
False cypress, Chamaecyparis
some Pines, Picea
Fir, Abies
Eastern Arborvitae, Arborvitae occidentalis
Here is the list of trees which accept shade : click here.
The most salt-tolerant species are :
Tree of Heaven, Ailanthus altissima
Arbutus, Arbutus
Cork oak, Quercus suber
Evergreen oak, Quercus ilex
Blackberry with leaves of plane tree, Morus platanifolia
Russian Silverberry, Elaeagnus angustifolia
Olive tree, Olea europea
Wych Elm, Scots Elm, Ulmus montana
Pterocarya in leaves of ash, Pterocarya fraxinifolia
Wisconsin Weeping Willow, Salix alba
Goat Willow, Salix caprea
Resistant to the saline spray :
Hawthorn monogynous, Crataegus monogyna
Wood of St Lucia, Prunus mahaleb
Birch, Betula
Wintersweet or odorous Wintersweet, Chimonanthus praecox, Chimonanthus fragrans
Maple of Montpellier, Acer monspessulanum
Norway Maple, Acer platanoides
Sycamore, Acer pseudoplatanus
Eucalyptus
Ash, Fraxinus excelsior
Holly, Ilex aquifolium
Southern magnolia, Magnolia grandiflora
Chestnut tree, Aesculus hippocastanum
Gean, Prunus avium
White mulberry, Morus alba
White Poplar, black, trembles, Populus alba, nigra, tremula
Pittosporum, Pittosporum tobira
Pissardi Cherry Plum, Prunus cerasifera
Tamarisk, Tamarix
Crimean Linden, Tilia euchlora
Very resistant to the saline spray :
Araucaria of Chile, Araucaria araucana
Cryptomeria of Japan, Cryptomeria japonica
Cypress of Monterrey, Cupressus macrocarpa
White Fir, Picea pungens " glauca ", sitchensis
Pine of Alep, Pinus halepensis
Laricio pine, Pinus laricio "forms"
Maritime pine, Pinus pinaster
Umbrella Pine, Pinus pinea
Scotch Pine, sylvan Pinus
Resistant to the saline spray:
False Cypress, Chamaecyparis
Umbrella Pine of Japan, Sciadoptys verticillata
Fir pectinate, Abies pectinata
Douglasfir, Pseudohemlock douglasii
Grand Fir, exaggerated Abies
Western red cedar, Arborvitae plicata
Eastern Arborvitae, Arborvitae occidentalis
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