Record warmth in southeast

[Beatrix Kiddo]

I agree it has been a warm April and there is also a bit of mice plague on around the city. Although i find when looking for local indicators using exotic species of deciduous trees, berries, and fruit trees a less than ideal considering they are on non-local native. Exotic trees around Melbourne are suffering badly and compensate in many ways by leafing out late, shedding early, and holding leaf which is at complete odds to the naturally occurring flora.

[WeatherGazer]

I thought I heard on the ABC radio, that the last few days have been well below average especially in places like Stanthorpe?

[droughtbreaker]

The Autumn colour display is usually spectacular here owing to the fact that the whole township area of Macedon and Mount Macedon (along with Gisborne and Woodend) is covered in established northern hemisphere deciduous trees and we have a climate very similar to Northern Europe, especially the higher parts of Mount Macedon above 700m where the average annual temperature would be similar to most sea level areas in England. The very reason the area was planted so extensively with so many species of exotic northern hemisphere trees was due to this climate and also (on a side note) the red volcanic soil which is excellent for plant growth. You can substitute Mount Macedon with the Dandenongs if you wish because they are very similar areas geographically, similar temps. similar rainfall, very similar geology, similar horticulture.

We have had ordinary Autumn displays in the past but this year would have to rate amongst the worst and it is all due to temperatures well above average and in particular extremely warm minimums.

We did get a period in April when things were starting to look good and we did get a few pockets with decent colour, certain species of trees did better than others, in particular the North American species seem to have done better than the Asian and European species for some strange reason. However only about a third of the leaves changed (the outer third) and when we got the warm spell these leaves started to brown and then some windy days blew them all off. Now we are left with mostly green leaves on the trees (the inner leaves) and some trees haven't changed at all and tomorrow is May. Wind is often a factor and many years blows the outer leaves off before the entire tree has a chance to change but this year there has been very little progress in general.

Strange, because now we are getting cold nights and days but still there is not much happening. I have heard that as CO2 levels rise trees hang on to green leaves longer regardless of temperature change, this combination of CO2 and rising temps is causing the same problems in northern hemisphere forests as well not just in the gardens, parks and streetscapes of SE Aus.

Worth mentioning that the last several years have ended up with pretty decent colour, even with the March 2008 heatwave and then events of last summer taken into account. It has a lot to do with extremely high minimums, they have been running up to 3C to 4C above average in recent months which is a straight out killer if you want decent Autumn colour to form.

[Beatrix Kiddo]

What sort of turf do you have hillybilly? A good judge of how much warmer things are at present will be when the summer active turf goes into dormancy, usually once the soil temps goes somewhere below 13-15 degrees, which is determined by the overnight minimum not the day time temps. I have to mow year round as i have summer active and winter active turf and at present both are growing well.

[mutley]

I watch and read this post with interest, however, have one (1) simple question. Is the temperature measured and reported against the days high or the days average temperature or perhaps something else like average temperature between 6am and 6pm.

Just curious.

[Anthony Violi]

This April was the 19th warmest for Melbourne, which must have been cold as it dragged it back to 0.7 above the average.

I agree about the grass, never mowed so much the last 8 months. I have a suspicion that 3 times the rainfall of the last 4 years may have something to do with it as well, this is the first year that the grass never browned off, during March it tinged a bit but other than that its a lime green jungle.

[droughtbreaker]

Yeah, lawn grass didn't die off this summer except for a few tiny patches for a brief period in late summer. It's very green atm, grass has grown heaps in the last few days and now the paddocks are starting to green up also. The entire range is fully green atm but it will take a little longer for all the surrounding paddocks to grow back from summer dormancy.

The most heartening thing is how green the forests and bushland are. There is a lot of native grass growth on the ground and there has been a lot of fresh growth. The last several years the same bushland/forest areas have been a straggly dustbowl with majorly significant die back of trees and shrubs, minimal wildflower displays in Spring etc. We are set for an excellent spring display in gardens and native forest this year as most of the flower and leaf buds development in deciduous and northern hemisphere plants is in Autumn before plants go dormant over the winter and native and evergreen plants will stay alive and healthy even if winter and early spring rainfall is low because evaporation is minimal to non existent during this time and the soil stays moist with little rainfall. Many places in Europe have average rainfall the same as the western suburbs of Melbourne but cool temperatures and low evaporation ensures the landscape remains green and flower and foliage displays are excellent most years.

The Camellia sasanquas are looking fantastic this year and the Camelia japonica buds are already well advanced with a few even attempting to flower (normal flowering time of Camelia japonica here is July to November). It is a similar story with most of the other northern hemisphere plants in the garden. In previous autumns the rainfall during the crucial stage of bud development in Late Feb to early April was very low and extreme high temps combined with this to cause anomalously high evaporation. Last winter/spring we hardly had any camellias flowering at all, it was easily the worst display ever. We got good rain from late Autumn and continuing now but it was too late for spring flowering plants that set their buds in autumn. Even wattles failed to flower, seriously we had no silver wattles flowering here in late winter/early spring last year when usually the forest is full of these trees blossoming.

This all ties in with how closely following environmental events and comparing to what normally happens can give us the best idea of what is happening to our climate.

[Anthony Violi]

Didnt melbourne Average Max come in at 21.0? I just worked out manually, but i geuss if it wasnt 21.0 then it wouldnt be.

[droughtbreaker]

Anthony, you should know about the Daily weather obs. section on the BOM website.

http://www.bom.gov.au/climate/dwo/20100 ... 1004.shtml

April average was 22.9C which came in just behind 1993 as the third warmest April on record. 2005 was the warmest.

[Anthony Violi]

Yes I do Andrew I was going by max, not both max and min.

Sorry I should have cleared that up first.

[Beatrix Kiddo]

The grasses are going along wonderfully but as Anthony pointed out i think that the soil moisture more so than the heat that made it go nuts. Also importantly the nitrate laced rain that we have had since October from all the thunder storms has been free fertilizer falling from the sky. I have noticed since black Saturday that all the exotics in my garden are all over the place, i have jap maples autumn dropping leaves on one side and new growth on the other.. I have a 60 year old pin oak in my yard that is struggling compared to the same age gums right beside it that are thriving. Interesting i went and had a good look around the yarra flats a while after the 46 degree day and the naturally occurring plant life just laughed off the heat where the exotics in nearby houses were torched. Clearly the natives have experienced temps of that magnitude before, they didn't burn or drop leaves or limbs like the exotics. The drought has been a god send in terms of changing our thinking when it comes to having European style gardens and inappropriate planting like cool season grasses.

[Karl Lijnders]

I did remember having a conversation with a local in Kallista about the damage to the trees and the rate of the bigger Mountain Ash dying in the gullys as you go along the Monbulk/Belgrave rd down towards Belgrave. He says that these trees are stressed with this extensive drought. I can say that it concerns me greatly seeing these prehestoric trees dying. I beleive they live on and on and on....they were 100m tall before I was here and they should be still there when I go.

Interesting times. But the influence on rainfall has been somewhat fascinating. Storm activity has increased in this hottest year.

[Anthony Violi]

Interesting prediction on the first post...but a spectacular fail by all the models related to the BOM.

Our coolest and wettest winter and Spring in many years, and yet for some reason Jan is tipped to be dry and warmer than normal.

EC has been bullish on colder and wetter since winter, has been spot on, so looks like records for rain and temps will continue this coming summer.