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HABITAT 4.
HIGH ALTITUDE TROPICAL
or
HIGH LATITUDE HABITAT
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The final habitat to be discussed.
This habitat is found in two situations -
- In tropical regions, at high altitudes, where cooler conditions are experienced, and
- High latitude areas such as New Zealand
In tropical countries this habitat exists at an altitude above Habitat 2, generally extending
from 1850 metres altitude to the permanent snow line, characteristically at some 3500 metres altitude. Our discussion
will concentrate on the tropical habitats as this is the source of most orchids of interest culturally.
Plants in culture commonly found here include some cymbidiums, odontoglossums, coelogynes,
and, of course, at our high latitude situation, our own native orchids. The climate is characterised in the tropics
by:-
- Fogs and mists prevalent for much of the year
- Light levels high during the winter, more shaded during the summer months
- Cool conditions
- Constant air movement
- Subject to the monsoonal conditions experienced in the other main habitats in tropical
areas.
- There are some epiphytes, but terrestrial orchids predominate, especially at the highest
altitudes.
- Climate conditions are relatively stable at the highest levels, with some seasonal variation
more apparent at the lowest levels merging with Habitat 2, although there are seasonal temperature variations.
From the tropical areas, as one travels to higher latitude localities, cooler temperate
areas will be reached, and New Zealand lies in such an area Epiphytes are generally found here to a limited extent
only as the cooler conditions are not conducive to their growth. There are, however, many terrestrial orchids able
to thrive under such conditions.
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With respect to this habitat, both the ALTITUDE and the LATITUDE and the environment influences
its character. Gilbert, in his book “The Charm of Growing Orchids” has quantified this relationship, and the chart
shown above illustrates this. If you know the altitude a plant comes from, and the latitude of the country concerned,
you can quickly gain an approximation of the temperature conditions likely to be applicable for that plant.
The typical climatic factors applicable to this habitat are a typical temperature range
of 0-25oC. although the normal range is 5-18oC. The diurnal range is 15oC. Humidity normally falls between 25-55%,
the lowest average of all habitats.
Plants cultivated from this habitat require cool conditions all year, with humidity between
25-55%. Relatively constant conditions are required, with good air movement. Winters are brighter, and summers
will be shaded.
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Typical rainfall data, and a comparison with Habitat 2, indicates generally high levels
of mm in precipitation, an annual rainfall of 1105 mm for this habitat, and 2076 mm for Habitat 2.
At this high altitude tropical habitat, the cooler temperatures can be expected. There is
also a significant seasonal variation experienced.
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The above can be extended by showing the extreme annual temperatures.
  
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GO DIRECT TO THE PAGES IN THIS SERIES
ORCHID HABITATS Part 1 INTRODUCTION
ORCHID HABITATS Part 2 Habitat 1 TROPICAL LOWLANDS
ORCHID HABITATS Part 3 Habitat 2 MONSOONAL FORESTS
ORCHID HABITATS Part 4 Habitat 3 ARID RAIN SHADOW INLAND
ORCHID HABITATS Part 5 Habitat 4 HIGH ALTITUDE TROPICAL AND HIGH LATITUDE
ORCHID HABITATS Part 6 SUMMARY
ORCHID HABITATS Part 7 APPENDIX - Paphiopedilum and Cymbidium habitat summary information
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