Silver Birch - Health and watering schedule

James Watt

Hi some questions on my Silver Birches

I have planted about 15 1.5M apart around a L shaped corner block. They were all mounded 10-15cm up.

Soil type is heavy northern Melbourne suburbs clay.

Soil dug down about 40cm, 1-2kg Gypsum per 1m2 was mixed in and watered in (apparently that helps). Soil was 80/20. 80% parent mix and 20% Certified organic compost. Both soils and gypsum mixed together by shovel in a wheelbarrow before upending into the dug out 600mm wide garden beds.

After say 40cm down though, is hard clay that resisted pick attack quite well and took ages to remove say another 5cm of it.
Obviously when the water hits this area it will slowly rise upwards like its an aquariam.

Drip pipe (Anti Syhon, pressure compensated) with 30spacing's and 1.6Lper hour drippers were installed with it running straight down the middle of the 600mm wide bed, then formed into a circle around the tree (roughly 4 drippers per tree) and on to the next tree. Watering period set automatically using a Galcon timer at 45mins every 4days. This was the watering setting from planting in June to Dec. Tank water used.

15 x 3m high bare rooted silver birches were planted in June 2008. All took up leaves in various intensities around September. Except one.It has never leaved yet when scratched displays green under the trunk. The best it had were these little green leaves growing out of the bottom of the trunk at soil level. See some of the pictures.







I have since removed this tree and placed a container grown example in its place, as of last week.

The other 14 birches, were all going quite well albeit with frustratingly different densities of leaves but the leaves were all 100% green. Watering period was increased slightly from about December to 45mins every 2days and then for 3weeks in late Jan to early Feb (inc the 46Degree Melb day) to once per day for 45mins. Now set back to 45mins every 4days only, which is about one sixth of the previous setting.

They are all now carrying partly yellowed leaves and some are not leaving on the lower branches and some lower branches are brittle and just snap easily.

Question 1: Any idea why the first birch did not leave when the other 14 did?
Does anyone know why it never had leaves appear?,

I can say its in the wettest part of the garden bed as its about 660cm from the end of the run, and the brown plastic coloured flush valve that is part of the drip pipe irrigation, often spurts out water alot when the system starts and stops. Could the water slowly be hitting the hard clay bottom and them moving along the bed and then obviously vertically up over time?

Question 2
Much more important that the first as its now taken out, I want the other 14 to survive, whilst I read here and elsewhere that Silver Birch do not take dry spells well, mine seemed to have turned worst with the increasing watering period I set to combat the summer heat. Could the clay be too waterlogged and starving it of oxygen and water uptake?

Question 3
Dry, brittle lower branches - what does that indicate?

Question 4
Is there anyway to get the lower branches to leave up, some of the 15 do some do not.

Eric Frei

I'll write my answers in this colour between your questions.

__________________

James Watt

Hi Ekka

Thanks for considering my questions

1- How do I perform a moisture test? other than simply looking and touching with my hand

2- As to mixing in compost, I actually followed the link from

http://www.baag.com.au/pdfs/soiladvisor.pdf

and
wetfeet
(see at the bottom right re the mix to avoid wet feet)

2a)Are you saying that compost should be mixed in to only say the top 20cm not 40cm? How would you prepare your soil to avoid wet feet with a heavy clay soil.
2B) Going from 45min per day to 45min every 4days (the original pattern for first 5months) would that help do you think?

3- Fertilizer burn - could be, I do use Seasol and Powerfeed fairly regularly - could that be it?

4- Thanks for that I will try to 'head' them back as you say, does head them back just mean cut them back? Sorry Iam just a beginner.

Thanks

Bernard Keays

James,

I think you have asked some really good questions. I'm not from Melbourne so my circumstances would be different to yours but we typically hand water new trees about once a week with approximately 10 to 20 litres of water per tree for the first 20 weeks. Watering with drippers is slightly different to hand watering. And if my math is right, you’re providing about 6.4 litres of water to each tree per watering cycle.

It might be worth thinking about increasing the amount of water applied per cycle while extending the duration between cycles. I prefer to water more deeply while allowing the soil to dry out between watering’s. If the soil becomes waterlogged, the roots stop growing and should this continue for an extended period of time they start to die from a lack of oxygen (unless of course the tree is adapted to deal with these problems).

Attached Files

04TS%20SOILS,%20WATER%20AND%20TREE%20ESTABLISHMENT_PeterMay[1].pdf (46.9 KB, 98 views)

__________________
Bernie

James Watt

Hi Bernard

Your pdf is quite informative, luckily when I planted the 15 bare rooted birches in June 2008, I did build a soil berm around just the rootball. I also made circles of the drip pipe roughly above just the rootball. So inline with your document not much else but the rootball was watered early on.



Watering Frequency
As you say Iam using about 6.4L per tree at the moment and this was the amount used for the first 6months to Dec08, until I changed it to 30min every 2days and then for 3weeks in late Jan , 45min per day. Its now back to 45min per 4days.

My leaves are all partly yellow and I realise this indicates a lack of water (is that all it indicates?), the problem for me is whether its due to not enough watering or too much and the roots are clogged down in the clay and therefore can not uptake any more water.



Any idea of what those hanging buds (warts) are? Does lack of water cause leaves to turn into those rather than leaves as the other trees do not have as many.





I think I will have to dig down around 4 or 5 of the birches to see how much moisture there is down there.

This is the pic of the tree that never leaved and was taken out



Here it is after being taken out, if you zoom in you can see that there is alot of moisture around the roots and the lower parts were quite compacted.




Soil Condition

Your document and Ekka mentioned that whilst it is beneficial to use composted organic matter to improve the soil condition, it should not be lower than 200mm otherwise anaerobic decomposition can occur and root growth will stop.

Whilst I at least learnt to not just remove the parent clay soil and add new compost only (aquarium), I used 80% parent vs 20% compost throughout my hole. Ie. more than 200mm deep. That said, this was done across all birches and at least for the first 6months with a 45min every 4day watering cycle it was fine, the bare rooted trunks went from leave less to varying degress of leaves.

Here is a picture of another garden bed closeby, but similar to the one the birches were planted in.



These clay sods were picked and dug out in the next 2 pics





Here you can see the claybreaker brand and compost I used to fill the 40-50cm dug down beds. As mentioned this was in a 80(parent soil) to 20(compost) mix with 1-2kg of gypsum throughout. All wheelbarrow mixed and then poured in. I did cover that very hard clay base with gypsum and water it in but I doubt it has started to break it down.

Attached Thumbnails

           

       

Eric Frei

Clay breaker and Gypsum Myth:-

If I had a dollar for every time that spin was used.

Gypsum only works on sodic soils, how many arguments I've had with places that flog product is incredible.

Source: Soil and roots

No doubt you would have heard or read about using gypsum to break up clay soils, it's even written on most packets. Gypsum can only improve clay soils that have sodicity. The sodium particles are displaced by gypsum from the clay. This is different to salinity where chloride is present. Only if it were that easy to just sprinkle some gypsum and problem solved, but farmers have long ago invested in ripping and organic green crops to till organic matter back into the soil. You can do a sodicity test, called the Emerson Dispersion Test to see if in fact your soil is sodic.[/QUOTE]

Source: Gypsum and Clay Factsheet - Gardening Australia - ABC

I would say you have a combination of fertilizer burn and over watering (wet feet).

How would I have constructed a bed in those conditions?

Washed drainage gravel/aggregate floor 100mm deep topped with sand/loam mix, mulched on top (prior to mulching I would have treated with wetting agent, organic fert like dynamic lifter, some mychorrizal fungi and worm juice to expand root system absorption and defend against parasitic fungi).

That bed could still fill like a pool so a raised bed would have been suggested, or adding overflow ag drain to rid a flood. When you create a well, water will accumulate there not disperse, a potential winter issue in Melbourne with low evaporation rates.

Here's a link to a similar case study up here:-
Juvenile poinciana problems - case study

__________________

Bernard Keays

Judging by your photos, I would say that your trees are being over watered. I would stop watering them every 4 days and extend this out to at least 7 to 10 days.

The soil needs to dry out between waterings. This is influenced by the season, weather, aspect, soil & surrounding vegetation. Some text books will talk about crop factor...

They're called catkins. If my plant anatomy is correct, they're a flower structure designed for wind pollination. They don't have any petals. And there are male and female catkins. The males hang down.

__________________
Bernie

aphid

you may need to devise a way for the excess water to drain away from the soil. is there any grade to the property?

James Watt

Hi

I will push the watering schedule out further as mentioned.

There is no grade unfortunately, the best I could have done, was when the beds were excavated to dig in some aggy pipe, properly covered on an angle and then connect it to the 6inch drainage piping leaving to the road.

Or made a run of 50mm aggy piping out to the road.