Tree Logic Arboricultural Consultants » Observations in the field

Healthy soil, potential breakthrough research

Stephen Frank — Mon, 05 Jul 2010 05:44:15 +0000

Healthy soil differs from dirt in the myriad of life forms it contains. Soil organisms (the biological properties of a soil) aerate, decompose plant material, assist nutrient absorption, build soil structure, reduce water requirements and play a vital role in the nitrogen cycle.
A proper balance of nutrients and pH obviously play a significant role in healthy plant growth. Biological activity can also affect the pH of the soil and subsequent impacts on the utilisation of of nutrients.
The biological properties of a soil decompose the organic matter in the form of litter falling on the soil surface and subsequently incorporates it into the soil profile. Nutrients are released as by-products, including the mineralization of nitrogen and nitrogen fixation (making nitrogen available to plants). The soil’s physical properties, including moisture content, temperature, aeration (bulk density) pH and nutrient content are necessary for a diverse soil organism population and a high level of activity. Limiting any of these factors limits soil organism activity, organic matter cycling and subsequently reduces soil fertility.
The undisturbed forest soil has organic layers in it’s profile. These organic layers comprise leaf litter at the surface, a decomposition layer and a humus layer. These large, high-molecular-weight molecules are made up of carbon, nitrogen, soil minerals and soil aggregates. The resultant humus is a stable, inseparable part of the soil matrix that can remain intact for hundreds of years.
When OM is incorporated into the surface soil it forms the topsoil (A horizon) and this horizon has the most optimum conditions for plant growth.
Urban soils are generally highly disturbed soil environments that do not mimic the soil conditions of natural forest soils. Human activity is the predominant agent in the formation of urban soils. Urbanisation also contributes unique amendments and contaminants to the urban soil.
Disturbing soil profiles, mixing and filling, and contamination lead to variability. This can also lead to compaction; restricted aeration and water drainage, crusting and bare, often hydrophobic surfaces. Importantly, interrupted nutrient cycling and modified soil organism activity result in unhealthy (low vigour) growth and predisposes plants to other environmental and biological stresses.
Tree decline is as a result of several interacting factors, such as prolonged drought, competition with adjacent trees, pest and disease infestation and generally depleted soil environments. Poor soil structure is a significant predisposing stress factor for plants. Poor soil structure affects water infiltration and permeability, water holding capacity, aeration status and loss of pore space. If plants do not have access to sufficient water and oxygen they will decline.
Healthy soil requires organic matter (OM); it aids in aggregation (soil structure), cation exchange (storehouse of nutrients) and water holding capacity. But most importantly, it sustains biological life in the soil; the greater amount and diversity of biological life there is in a soil the greater potential for healthier plant growth. Soil health is the basis for plant health and by extension, healthy plants can help develop healthy humans.
Tree Logic has commenced a trial to incorporate humus into urban soils. Ninety established Plane (Platanus spp.) street trees exhibiting decline symptoms, were treated using liquid humus, Seasol® and urea. A number of trees in parks and reserves within an eastern Melbourne municipality were also treated.
A sample of the trees to be treated along with controls in close proximity that included healthy Planes and Planes displaying similar malaise were established prior to the commencement of treatments. The samples looked at current season shoot tip extension and leaf size. In addition, leaf samples were fluoresced and data captured on short and long term stress indicators. This data will be compared against future samples to determine the efficacy of the treatments over a 2 year period.
Injecting liquid humus into urban soils will start to build up the organic content of the soils which will aid water holding capacity, cation exchange capacity, and reduce leaching. Organic matter can also buffer effects of any pesticides and stabilise pH. Treatments are carried out in autumn and spring (before bud burst). Humified carbon differs physically, chemically and biologically from the labile pool of organic carbon that typically forms in agricultural soils. Labile organic carbon arises principally from biomass inputs (such as leaf litter) which are readily decomposed.
In conjunction with the liquid humus the soils can also be injected with liquid nitrogen. In degraded urban soils the major nutritional limitation on plant growth is lack of nitrogen (Pulford, 1991). Without an adequate pool of organic nitrogen, which microbial activity breaks down into forms (NH4+ & NO3-), mineral nitrogen is quickly depleted in soils and nitrogen deficiencies develop. Low organic matter content is typical of urban soils consequently nitrogen is the nutrient most limiting to growth (Roberts, Jackson, Smith, 2006).
The other consideration is the on-going nature of the applications, that is, to be successful a number of applications will be required. Products, application timing and rates and costs could be developed upon request.

Fig Tree Planting at the Grand Hyatt, Melbourne

David — Wed, 27 May 2009 04:58:46 +0000

The redevelopment of the Hyatt’s Foyer is complete and the five Ficus hilli var. ‘Flash’ installed by Tree Logic are prospering in their purpose built habitat.

The project presented many challenges none less demanding than balancing the horticultural requirements of the plants against engineering constraints, interior design requirements and construction schedules.

Tree Logic was involved with the designers from the outset providing advice that ensured adequate soil volume was designed into the floor space, specifying soil media appropriate for growth that meet ?oor load restraints, securing appropriate species of a large enough size to create an impact and advising on appropriate artifcial lighting requirements to sustain the three trees that were located within the building.

That was the easy part.

The installation of the trees was undertaken in conjunction with the construction process which was demanding to say the least. Getting the materials we required including almost 70 cubic meters of soil media and five 6 meter tall trees weighing 1.2 tonne each into the site from Collins and Russell Street was a challenge in itself that was compounded by tight deadlines, even tighter access and the need to protect expensive floor coverings. Once we were in, drainage had to be installed, the soil media had to be carefully layered within the pits, the trees set, irrigation installed, moisture and temperature monitoring equipment fitted all completed whilst a myriad of other construction activities went on around us in close proximity.

In the final phases of the construction process, Tree Logic also had to ensure that the trees and the pits were kept free of building debris such as plaster and stone dust whilst monitoring and testing our systems.

With that all behind us, Tree Logic is now charged with the responsibility of maintaining the trees over the expected life of the design and developing their form to suit the space and, in time; create spectacular indoor trees.

Tree Logic would like to thank our staff, GHG, Bar Studios, Billard Leece, May Horticultural, Kanes Construction and Irene Gosney to mention a few for their patience and support through the delivery of this project.

Heritage tree saved in Traralgon

Stephen Frank — Wed, 26 Nov 2008 22:24:10 +0000

In October, Tree Logic was set the task of transplanting a large maturing Azarole Hawthorn (Crataegus azarolus) located in old Salvation Army site where it had been planted 60 years earlier, to Victory Park in the very heart of Traralgon which is literally across the road.

The tree is listed on the Victorian Heritage Register as being of state botanical significance as the only known example of this specie or hybrid in Victoria. With the help of Rob Bodenstaff (Arbor Centre, WA), BS Callow, Gyra Engineering and various local sub-contractors including P & D Cranes, Maffra Trenching and RTL Transport; Tree Logic set about process for transplanting the 40 tonne tree.

How we did it

A root ball of over 5 meters in diameter was carefully excavated, roots were trimmed and the ball framed. A steel raft frame was constructed under the tree so that it may be lifted with a crane and placed on a transport vehicle. The base lift method of transplant was chosen over the more common practice of pin lifting, to reduce damage to the tree and to take a much larger root ball. Once lifted on to transport the tree was driven across the Princess Highway into Victory Park. The tree was planted proud of existing site grade to avoid any potential water logging of the root ball, was mulched and the site cleaned up.

The job was completed within 5 days. LaTrobe City Council will look after the tree for the next 2 – 5 years until it becomes re-established in the landscape. Parks and Gardens staff lead by Mick Cantwell were trained by Tree Logic in the nuances of managing and maintaining the tree over this critical period and we will be dropping in from time to time to see how the tree fares. Early indications are that it’s a happy team at Hawthorn.

Red Maple borer attack

Stephen Frank — Tue, 14 Oct 2008 01:32:36 +0000

A recent letter from Peter has been answered by Stephen Frank at Tree Logic and so we include here as advise to those with similar problems.

Hi
My name is Peter I have a problem with my maple tree in the back yard.
Can you help me with a grub that seems to be eating the crotches and trunk of this Acer rubrums.
It is a young tree.
If I send some photos can you please give me a consultation? Possibly a way to save the tree from getting worse as we love the tree I am happy to pay you for your time
Regards
Peter

Hello Peter,
Indeed your Red Maple has a problem, and to be honest one that can not be solved by any arboricultural treatment I am aware of.
Judging from the photo accompanying your email, the pest has been present for some time and extent of damage is too much. It would appear that ~50% of the circumference of the stem has been affected.
Control of borer in trees is very difficult. Most borers attack trees weakened by drought, mechanical injury, recent transplants, poor soils or root systems. The most important prevention of borers is keeping trees healthy through proper management (primarily watering, which again can be difficult under current drought conditions). The most common way to control borers, in addition to proper tree maintenance, is chemical control. However, borers live inside trees, and treating them with insecticides is difficult if not impossible, and it comes down to timing of treatment. The best time to control borers is when adult are laying eggs on or under bark, which is difficult to monitor in a domestic situation. Pheromone traps, available for some borer species, help determine if adults are present. Trunk sprays can be effective when borers are in the early larvae stage before they enter the tree. I reiterate that the extent of damage with your tree suggests that the tree is past chemical treatment. I have heard people using a fine wire to poke into the tunnels created by the borers in the hope of skewing one.
I would suggest you remove the tree (as distasteful as it sounds) and replace it with a new one. Properly plant species that are well adapted to your location and provide them with proper care. Avoid pruning from spring through summer when adults are active. Protect trees from injury. Remove and dispose of dying limbs and dead trees. Do not pile fresh-cut wood near trees.
I hope this helps.
Sincerely,
Stephen Frank

An analysis of the Street Tree Population

Stephen Frank — Tue, 02 Sep 2008 05:00:49 +0000

An analysis of the Street Tree Population of Greater Melbourne at the beginning of the 21st Century

Download the pdf of the Paper published in Arboriculture and Urban Forestry.
Written by Stephen Frank, Glenn Waters, Russell Beer, and Peter May.
An analysis of the Street Tree Population of Greater Melbourne at the begining of the 21st Century.

Click to download the pdf

Nothing Gets in the Way of Tree on the Move!

Stephen Frank — Fri, 30 Nov 2007 02:11:37 +0000

If your task was to move a 14 metre wide by 6 metre high tree and you were unable to use a crane because of high voltage power-lines would you give up? Many would – but not the determined Dave Balsamo and team. Here’s the hot tip. It is definitely easier to move house than to move a large tree. The 26 year old treasured Quercus robor’s (English Oak) journey began last year when Tree Logic was engaged by Caroline and Don Hume to move the tree from the entrance of their property in Farm Road, Werribee to the garden bed immediately outside their house. The land was to be subdivided they wanted to ensure the future of their much loved tree. Tree Logic prepared the root ball and pruned the tree in July 2006 and over the following summer assisted the Hume’s in maintaining the tree. Carbohydrate drenches were employed on the root ball of the tree to promote root initiation and elongation. That was the easy part. Next came the actual move in August this year and the realisation that a crane could not be used to move this beauty. Determined to find a solution, Dave and his team tapped into much creativity and a bit of early Xmas spirit. The tree’s root ball was framed, lifted, placed on a sled and moved 600 meters to its new location.

Tree Logic is providing the initial establishment maintenance including carbohydrate drenches, and has developed an establishment maintenance program that will be delivered by the Hume’s over the next three years to ensure the tree’s health and future prosperity. Dave is contemplating starting his own human dog sled team! Well done Dave and team.

Struggling Oak gets a treatment

Stephen Frank — Wed, 28 Feb 2007 04:52:38 +0000

Struggling oak getting a “Carbo drench” and possum guard skirt. It also needs pruning back from the roof to be possum proof.

Pictures are of James at work. Click to enlarge.

Tree holds up traffic sign

Stephen Frank — Wed, 28 Feb 2007 00:04:30 +0000

Interesting photos of an arborial reaction to traffic management.