Re: (Metrosideros) Bloom seasons in northern and southern hemispheres

Jason D wrote:

> Moira wrote:
>
>> None of my books so much as mention it [M. angustifolia) quite
>> possibly it is not very garden worthy.

Dear Moira,
> I'm always delighted with the thoroughness of your replies. Thank you
> again.
My pleasure

Metrosideros angustifolia plants here look like a very short,
> upright, wispy Agonis, with yellow-green leaves and reddish new
> growth. Not much to write home about.

Thanks for confirming my guess.

>> I doubt though temperature differences are seriously involved. I
>> don't think California is likely to be any cooler around the summer
>> solstice than Wellington is. Its highest temp at this time of year
>> would certainly very rarely exceed 24 C (75F) and at this temp we
>> get the most glorious concerted show from every tree around,
>> lasting about a month, and generally dazzling the eye..As to
>> California being drier, this would probably be an advantage.
>> Wellington tends to be rather on the moist side around Christmas,
>> while the original habitat could already be quite summer dry.

>
> Sounds like we should import seed of Pohutukawas flourishing around
> Wellington.

They certainly might be better adapted to a cooler climate than ones from our northern parts. As far as I can tell the local plants are all pure M excelsa anyway, as I have never seen any tedancy to diffuse flowering locally nor for that matter any M kermadecensis offered in our local garden centres..

I don't know though how you could get seed, as I am pretty sure the packet seed commercially available in one of our local garden centres is from northern collections. However I could, if you should be sufficiently interested make some enquiries. Possibly the local Forest and Bird Society branch could oblige.

>> You can't really generalize anyway about the climate of the North
>> Island, as its long not very wide form means there is around five
>> hundred miles difference between Wellington at its southern tip and
>> the tree's natural southern latitude boundary  (a difference
>> between a mid-temperate and a warm temperate climate in fact).
>
> > Just as here in California we have 20 different major climates >
> across
> 10 degrees of latitude and 14,000 feet of altitude. Just across the
> seven-mile width of San Francisco there are microclimates where
> Jacarandas bloom profusely and beachside sites where even
> Bougainvillea won't bloom for lack of heat. There are forests of
> exotic trees on hilltops that sustain epiphytic ferns with fog drip
> during our six-month drought, while most untended grassy hillsides go
> brown by May.

Though we cannot match your main mountain chain for height our Southern Alps do go up to an altitude sufficient to give them a permanent cap of snow. The highest peak being Mt Cook/Aorangi which until a few years ago was 1249 ft high, when it had a small accident to its summit and lost about 20 or 30 feet in a spectacular avalanch. Some climbers had lucky escapes, but fortunately nobody was even hurt.

> How low are the rainfall totals in that South Island rain shadow?
> What is the range of summer/winter temps in that continental-type
> climate? What city(-ies) would best represent either or both
> phenomena?

I have a splendid NZ atlas with all sorts of information about climate, but getting just the simple figues you are asking for proves to be quite difficult. What definitely stands out is the difference in annual rainfall between the western coastal strip and the plains on the other side of the mountain divide. The entire west coast comes in the area which expects from ten to twenty FEET of rain a year while on the plains in the rainshadow the range is roughly from 30 down to 20 inches, with a few areas expecting no more than 15 inches annually. The west coast rain falls typically on 175-200 days each year while on the plains it rains on average on no more than 100 days, mostly in the cooler months and with much of the central area expecting precipitation on less than 75 days. Of these totals quite a bit of the winter precipitation falls a snow, but this is rarely long-lasting most commonly disappearing almost immediately or lasting no longer than two or three days. heavy winter frosts, including hoar frost, and often accompanied by freezing fog are common in the higher parts. There are ponds and small lakes towards the foothills which regularly freeze over thickly for part of each winter allowing the citizens of Dunedin to remember their Scottish ancestory and to indulge in the game of curling. people also go there jsut to skate.

This is an area which in summer will experience between 20 and 30 days with temperatures above 77 degrees. This may not sound much but it can in fact be a whole lot higher at times I have been in a car travelling across the Canterbury plains from Mt Cook village to Christchurch when the temperature was running at 100 degrees F along our route and even higher (104 degrees) at one town we did not touch on. The temperature in Christchurch the day we arrived and the next one held at 100 before dropping back slightly.

In contrast the maximum temperature in my home area (a valley in the hills close to Wellington) never goes above 79F and many summers will not even exceed 77F and you can see the degree of "continental" climate South island manages to achieve, narrow as it is..

You were asking about cities showing these traits. I guess both Christchurch and Dunedin come within the rainshadow area, but both have climates influenced by being close to the east coast and so modified a good deal both in temperature and rainfall. In the dry plains of inland Canterbury and Central Otago there are certainly no cities, only small farming towns far apart and separated by dry, sheep-grazed plains. Almost all these towns are situated on or near the several braided rivers which meander east from the moutains entering the sea at fairly regular intervals along the coast on that side of the island. Most of these rivers originate in long narrow lakes running down from the range and these are well-known for the excellent holiday resorts which are sited around theor shores.

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