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Eucalyptus, not just timber: ecological restoration via phytoremediation

Ecological restoration... by planting Eucalyptus

(Ironías al darle la vuelta a la tortilla... verde)

Gustavo Iglesias Trabado

GIT Forestry Consulting - Consultoría y Servicios de Ingeniería Agroforestal - www.git-forestry.com

EUCALYPTOLOGICS

Trees with bad press, frequently associated to ecological degradation, soil and/or water depletion or the already too wasted mantra "nothing grows under gum trees", Eucalyptus can be exactly the opposite. Today we see a case of phytoremediation in which these trees are used in three different but complementary ways.

1) Eucalyptus as fast growing pioneer species to cover denuded soils

Eucalyptus bioremediation plantations in Galicia, Northwestern Spain. GIT Forestry Consulting

Fig. 1: Terraces of an abandoned copper mine are progressively afforested with Eucalyptus (in this case, E. globulus ssp. globulus)

Their fast growing new vegetation cover will contribute to minimise soil erosion and lixiviation of hazardous heavy metals to aquifers or river systems by controlling direct rainfall impact effects on bare soils and by retaining it with their root systems.

Their plasticity adapting to different site conditions allows them to grow on extremely recalcitrant soils for plant colonisation overcoming extreme acidity and lack on nutrients with a proper preparation of the new planting area.

Their extreme efficiency producing biomass from limited resources allows a quick deposition of organic matter on denuded soils, creating new superficial horizons (topsoil) to substitute those eliminated by mining operations, which will later allow successful survival of other types of vegetation in places where it was previously impossible.

2) Eucalyptus as recyclers of organic residues generated by different industries

Eucalyptus recycle organic residues from industry in Galicia, Northwestern Spain. GIT Forestry Consulting

Fig. 2: Soil ammendement with residual urban sewage sludges helps Eucalyptus establishment via input of easily available nutrients

Their ability to survive on extremely unhospitable soils is aided by the application of different elements able to ammend critical soil properties and favour a quick development of a new tree cover.

Solid fractions of residues from urban sewage water treatment plants, milk processing industry sediments, residual solid fractions from cellulosic pulp mill industrial processes, and calcium carbonate rich residual crushed shells from seafood processing industries find a safe place in which to degrade and release the initial load of nutrients that will be recycled by the trees and later added to the soil as degrading biomass to close a new cycle of nutrients. In addition, these residues now turned into subproducts do contribute to favourable physical and chemical properties of this artificial soil.

3) Eucalyptus as rhizofilters (green filters)

Eucalyptus phytoremediation as green filters in Galicia, Northwestern Spain. GIT Forestry Consulting

Fig. 3: Eucalyptus tree-belts acting as rhizofilters on heavy metal contaminated streams

Properly designed additional Eucalyptus tree belts strategically arranged along natural or artificial drainage lines act as a green filter when their roots capture heavy metal lixiviates that will be stored in tree biomass, avoiding immediate hazards of water contamination for nearby agricultural or urban areas.

In the medium term the accumulation of toxic water in decantation pools will be minimised, and with the help of other resistant herbaceous plantings and these and other fast growing trees cultivated in sequential stages, new soils will start to develop where there was none.

(1+2+3) Eucalyptus as successful tools for Ecological Restoration

Ecological Restoration by planting eucalypts yields in this practical case the following positive externalities:

Soil erosion control
Safe disposal of the organic residues generated by four different industrial lines
Immobilisation of heavy metals and other hazardous chemicals
Formation of a new soil that will support vegetation in future

Without forgetting a couple of classical benefits arising from tree growing:

Carbon sequestration, contributing to minimise climate change
The extra of timber production in a previously improductive land

What a trip... from "nothing grows under gum trees"... to "nothing would grow without Eucalyptus". Ironies of bioengineering.

Contact GIT Forestry Consulting / Contact Eucalyptologics / Contacto GIT Forestry Consulting / Contacto Eucalyptologics / Lugo, Galicia, Spain, España

Contact GIT Forestry Consulting - Eucalyptologics

GIT's Eucalyptology Topics

Eucalyptus timber: not just pulpwood

Cold hardy Eucalyptus timber production in Galicia (NW Spain)

COLD HARDY EUCALYPTUS TIMBER GROWING & HARVESTING
A pictorial review of Eucalyptus Forestry in the Highlands of Galicia, Spain

Gustavo Iglesias Trabado

GIT Forestry Consulting - Consultoría y Servicios de Ingeniería Agroforestal - www.git-forestry.com - EUCALYPTOLOGICS

Fig. 1: Example of Eucalyptus nitens tree growth (1): DBH-80 in less than 20 years. (Click to enlarge)

Fig. 2: Example of Eucalyptus nitens tree growth (2): DBH-20 in 6 years on a pulpwood silvicultural regime. (Click to enlarge)

Fig. 3: Cold temperate Eucalyptus pulpwood harvest operations in Galicia

1 - Basal logs: DBH-30 or bigger. Debarked on site and arranged on piles along a strip for easy operations of loading and extraction out of the forest.

2- Harvest coupe: 9 year old planting of Eucalyptus nitens (Shining Gum) at 500 m altitude on easily mechanisable tablelands.

3- Tree felling: Chainsaw operator approaching the new target and assessing the best tree felling angle. Depending on logistics of harvest this tree felling operation can be performed by an independent worker (as in this case) or by the machine at 5.

4- Typical tree: +20 meters high at a relatively high stocking (1100 trees/ha, could be less with no worries). 5 to 7 pulpwood logs per tree, 2 to 4 firewood logs per tree, 1 to 3 residual logs per tree.

5- Log processing: 4 step serial operations of handling, debranching, debarking and log cutting at desired length being performed by a forestry processor heavy machine.

6- Log loading and extraction: crane-aided loading on a timber trailer towed by a standard heavy duty agricultural tractor. From here to temporary loading yard for further loading on trucks.

7- Organic fertiliser for next crop: log processing residues (bark, branches, tree tops with leaves) remain on site to return the majority of nutrient uptake during crop maturation to the soil. They can be finely crushed in some weeks and later be partially incorporated during new planting operations as raw organic fertiliser or be arranged on strips and subject to controlled burning to use ash as fertiliser if season of the year and low forestry fire risk do allow it.

Interesting links

Sawn timber and furniture applications of Eucalyptus globulus wood in Galicia, Northern Spain / Aplicaciones de madera aserrada y mueble de Eucalipto globulus en Galicia, Norte de España / GIT Forestry Consulting - Consultoría y Servicios de Ingeniería Agroforestal / CIS Madera - Centro de Innovación y Servicios Tecnológicos de la Madera de Galicia

Tasmanian Oak: Roble de Tasmania in Galicia (NW Spain)

Snow in a 5 year old cold hardy Eucalyptus nitens timber plantation at 600 m above sea level in Galicia (Northwestern Spain)/ Nieve en plantacion de Eucalipto nitens (Eucalipto de las heladas, Eucalipto brillante) a 600 metros de altitud en Galicia (Noroeste de España) / GIT Forestry Consulting, Consultoría y Servicios de Ingeniería Agroforestal, Lugo, Galicia, España, Spain

Eucalyptus & Snow: Winter Views of eucalypt timber plantations in Northwestern Spain

Contact GIT Forestry Consulting - Eucalyptologics

GIT's Eucalyptology Topics

Eucalyptus flowers: E. nitens & E. globulus in bloom. Bees and Eucalyptus Hybrids.

Phenology of E. globulus and E. nitens in Galicia (Northwestern Spain)

Gustavo Iglesias Trabado

GIT Forestry Consulting - Consultoría y Servicios de Ingeniería Agroforestal - www.git-forestry.com - EUCALYPTOLOGICS

We have already seen some previous example of eucalypts blooming. Today we will see some more!

Shining Gum: Eucalyptus nitens flowers

Eucalyptus nitens flower buds bloom Shining Gum Eucalipto nitens flores Galicia España Spain GIT Forestry Consulting

Fig. 1: Examples of flower buds, blooms and infrutescences in Eucalyptus nitens growing in Galicia (NW Spain)

Widely introduced into commercial scale plantings in Galicia as a frost hardy alternative to E. globulus of the inland tablelands and ranges, E. nitens most commonly appears at altitudes between 400 and 900 m, growing in a variety of soil types and site conditions.

Its fast growth, small flower size (clusters around 1 cm), relatively delayed maturation age compared to other species and loss of basal branches when planted in timber stands can make spotting its blooms a difficult task without using binoculars. We have observed it blooming from late April well into July, but some variation in these phenologic ranges can happen every year depending on climatic tendences and some variation does occur also at different altitudes.

Tasmanian Blue Gum: Eucalyptus globulus ssp. globulus flowers

Eucalyptus globulus flower buds bloom Tasmanian Blue Gum Eucalipto blanco flores Galicia GIT Forestry Consulting Spain España

Fig. 2: Examples of flower buds and blooms of Eucalyptus globulus ssp. globulus growing in Galicia (NW Spain)

The classical species in the Atlantic coasts of Iberia (from Portugal to France), introduced in half the 19th century and widely planted in the milder coastal climates since mid 20th century, E. globulus ssp. globulus normally appears at altitudes between 0 and 500 m, also in a wide variety of soils and site conditions.

Spotting trees in bloom for this species is easy: it is one of the eucalypts with big flowers (3 to 7 cm diameter when blooming) and it does so profusely, covering the crowns with easily visible silvery white spots by the right time of the year and causing pollinator frenziness due to big amounts of nectar, which, keep me the secret, is also accessible to human beings and tastes certainly sweet. We have observed it blooming during winter and spring, from as early as late November to as late as the last weeks of May, with noticeable variation depending on tree age, microclimatic conditions and yearly climatic tendence making these extremes expand or contract depending on the year.

A jump ahead of seven steps: Eucalyptus "globens" or Eucalyptus "nitobulus"

For the sake of brevity (Bonum, si breve, bis bonum), after jumping from flower to flower "bee style", we jump ahead overcoming taxomomic, phisiologic, phenologic barriers, a bit more ahead overcoming seed collection, extraction and germination, a bit more ahead overcoming plant screening... et voilà!

Eucalyptus nitens x globulus Eucalyptus globulus x nitens Eucalyptus hybrid Eucalyptus nitobulus Eucalyptus globens Eucalipto hibrido Galicia GIT Forestry Consulting Spain España

Fig. 3: Example of Eucalyptus forestry species hybridisation: hybrid of E. globulus and E. nitens (E. nitens x globulus)

One of these days we will describe each small previous jump, and proceed further to yet another complex process: mass vegetative propagation!

The main driver should always be "Eucalyptus Heterosis can be exploited".

or, in the funny way...

Honey bee foraging a blooming ornamental Eucalyptus in Galicia, Spain/ Abeja pastando eucalipto en flor en Galicia, España / GIT Forestry Consulting, Consultoría y Servicios de Ingeniería Agroforestal

Heteroid Eucalyptus Yields: Breed Elite Eucalypts!
(HEY BEE!)

GIT's Eucalyptology Topics

Natural regeneration in Eucalyptus (4): E. gunnii, E. nicholii & E. blakelyi

Eucalyptus blakelyi gunnii nicholii coppice GIT Forestry Consulting Galicia Spain España

And yet more images on vegetative regeneration in Eucalyptus, in this case young potted plants experiencing a small coppice trial at nursery. As we had seen by now for planted out forestry species E. delegatensis, E. obliqua, E. globulus and some provenances of E. nitens, for these other forestry/ornamental species as E. blakelyi (Blakely's Red Gum, series Tereticornes), E. nicholii (Narrow Leaved Black Peppermint, section Maidenaria) and E. gunnii (Cider Gum, section Maidenaria too) natural regeneration from both lignotuber and axillary buds is frequent and vigorous.

Totally unrelated, some historic/taxonomic notes on these species:

- E. gunnii was named by W.J. Hooker honouring J.C. Gunn, two remarkable eucalypt botanists at Kew and Tasmania respectively in the late 19th century.
- E. blakelyi was named by J.H. Maiden honouring W.F. Blakely, two of the most prominent eucalypt botanists in the early 20th century and authors respectively of the Critical Revision and A Key to Eucalyptus.
- E. nicholii was named jointly by Maiden & Blakely honouring W.H. Nicholls (?). But if they had lived in the 21st century maybe they would have very seriously pondered if naming it E. nicollei instead!

Eucalyptus in Morocco: gum trees in the arid lands

LES EUCALYPTUS AU MAROC: BREVEMENT!

Eucalyptus plantation Guercif Morocco Maroc Plantacion Eucalipto Marruecos Pierre Arnaud Chouvy GIT Forestry Consulting Galicia España Spain

Fig 1: Eucalyptus plantation near Guercif (Morocco).
Photo courtesy of Pierre-Arnaud Chouvy (Photogeography)

Eucalyptus: Their place in Moroccan Forests

4.8 million hectares of natural forests (5% of territory).

Quercus ilex (Chêne vert, Encina, Live Oak, 29%)
Saharian Acacia species (Acacias sahariens, 21%)
Argania speciosa (Arganier, Oil Tree, 18%)
Tetraclinis articulata (Thuya de Berberie, 11%)
Quercus suber (Chêne liège, Cork Oak, 8%)
Juniperus oxycedrus and others (Genévriers, Junipers, 5%)
Cedrus atlantica (Cèdre de l'Atlas, Atlas Cedar, 3%)
Other forest types (5%).

0.5 million hectares of forestry plantations (less 1% of territory)

Conifers 47%
Eucalypts 40%
Broadleaved 13%

Fig. 2: Transplanting Eucalyptus at Sidi Amira clonal forestry nursery (Morocco).
Photo courtesy of Haut Commissariat aux Eaux et Forêts et à la Lutte Contre la Désertification.

0.2 million hectares of Eucalyptus plantations (less 0.25% of territory)

E. camaldulensis (River Red Gum, 48%). On siliceous soils.
E. gomphocephala (Tuart, 41%). On calcareous soils.
E. sideroxylon (Red Ironbark, 4%). On clay soils and arid conditions (lower than 300 mm)
E. grandis (Rose Gum, 4%)
Other Eucalyptus species (3%): E. tereticornis (suffers in very dry years), E. globulus (not enough rainfall), E. occidentalis (on arid chloridic soils), E. robusta (ill-adapted to drought, abandoned as forestry species), trials with E. brockwayi, E. flocktoniae, E. salmonophloia and E. salubris.

Eucalyptus planting Oujda Morocco Maroc Plantacion Eucalipto Marruecos Manfred Schwedan GIT Forestry Consulting Galicia España Spain

Fig. 3: Soil preparation for afforestation with Eucalyptus in the Oujda Plateau (Morocco).
Photo courtesy of Manfred Schweda (This Fab Trek: Navigating Morocco)

Eucalyptus are most common in the coastal Atlantic plains of Morocco from north of Rabat to south of Casablanca, in areas with annual rainfall ranging from 200 to 500 mm; but are also cultivated inland of the Mediterranean coast from Fez to the Algerian border (and beyond to Oran) as the images displayed here prove. They are also relatively common as specimen shade or garden trees elsewhere in the country.

With 200.000 hectares planted, Morocco ranks third among the countries of the Mediterranean Basin in what is related to Eucalyptus timber resources after Spain and Portugal.

Eucalyptus in North Africa: Looking half a century back through the eyes of Metro & Leloup

"Of French North Africa, Morocco has the largest area planted with eucalypts, estimated at about 25,000 ha. At present about 4,000 ha are being planted every year. Numerous windbreaks have also been planted (...) Certain sites are favored by their proximity to the sea. Other plantation areas lie inland and in the south of the country (...) Very few species have proved resistant to cold and snow. The upper limit for the practical use of euacalypts in Morocco seems to coincide with the lower limit of cedar distribution, about 1,500 m."

"In the neighbourhood of Algiers, especially where the species mentioned in connection with Morocco give or can give comparable results, fine specimens of the following species are found in various collections. These are less vigorous than those previously mentioned, but are of very fine habit.

E. amygdalina, E. andreana, E. botryoides (fine habit in cool coastal areas), E. bridgesiana, E. calophylla, E. cinerea, E. cladocalyx (very vigorous on the coast), E. cornuta, E. cosmophylla, E. crebra (vigorous), E. diversicolor (very fine and vigorous habit on the coast, particularly in cool areas), E. gomphocornuta, E. goniocalyx (vigorous on heights), E. hemiphloia (fairly vigorous), E. leucoxylon (fairly vigorous), E. longifolia (poor growth), E. maculata (vigorous on the coast, especially on the cooles sites), E. maculosa (poor growth), E. melanophloia (poor growth), E. melliodora (vigorous), E. obliqua, E. ovata (vigorous and thriving on heights), E. paniculata (mediocre), E. polyanthemos, E. propinqua, E. punctata (fairly vigorous on the coast on moist soils), E. raveretiana (vigorous), E. resinifera, E. redunca var. elata, E. rudis (vigorous, comparable to E. camaldulensis), E. scabra, E. siderophloia (vigorous in cool moist coastal zones), E. smithii (thriving on heights), E. trabuti (vigorous in cool moist coastal zones), E. viminalis (thriving on heights)."

Marcel Leloup/FAO (1955). Eucalypts for Planting

Note 1: remarked in bold, species with some interesting tolerance to frost
Note 2: please remember taxonomy is outdated for some taxa in this list
Advice: Crosscheck the list with Ian Barclay's Hardy Eucalyptus Database

Recommended Literature on Eucalyptus in Morocco

Les Eucalyptus au Maroc Morocco Eucaliptos Marruecos Achal el Kadmiri Fechtal Caisse Nationale de Credit Agricole

FECHTAL, M. & ACHHAL EL KADMIRI, A. (Eds), 1994. Les Eucalyptus au Maroc. Caisse Nationale de Crédit Agricole. VIII, 356 pp. ISBN 9981-9796-0-0 [Paperback].

WE DO NOT HAVE THIS REFERENCE IN OUR EUCALYPTIC LIBRARY. DONATIONS WOULD BE GRATEFULLY WELCOME (OF COURSE!)

(If you are to order it from somewhere, just order two copies and send me one to Spain!)

GIT's Eucalyptology Topics

Eucalyptus flowers: the case of paired inflorescences

When Eucalyptus behave strange: flowers that do not follow the usual pattern

Gustavo Iglesias Trabado

GIT Forestry Consulting - Consultoría y Servicios de Ingeniería Agroforestal - www.git-forestry.com - EUCALYPTOLOGICS

Double flowers: why?

Observe any new growth in your eucalypts, where the smallish new leaves are starting to form. You can see there that near the base of a pair of leaves (if juvenile and sessile) or near the petiole of adult leaves, in the axil, new small branchlets in development that will become soon new lateral branches.

Eucalyptus globulus Eucalyptus pulverulenta Eucalyptus neglecta paired inflorescences Eucalipto blanco Eucalipto de hoja de corazón Eucalipto neglecta flores pareadas Galicia Spain España Marennes Francia Mt Annan New South Wales Australia Phil Sydney Benoit Binson Marennes GIT Forestry Consulting

Fig. 1: Examples of paired inflorescences in three Eucalyptus species

This new growth is happening from an axillary bud, near the location of a joint between a leaf and a branch. It normally becomes a new branchlet if it is a vegetative bud, which happens all along the life of the eucalypt, and it becomes an inflorescence if it is a reproductive bud, which happens when the plant reaches reproductive maturity.

The issue is that this tissue that is dividing into new cells (hence growing) is not "unique". Buds can develop "more than once in the same axil". That is why you can have a new leaf first, and an inflorescence later, growing from the same axil. This is the most common case in Eucalyptus (not in Corymbia) and the reason for inflorescences being defined as axillary. In this case, the first bud is vegetative and the second bud is reproductive.

But in the pictured examples we are seeing something a bit of unusual, which is paired flower clusters. It is not the "common thing" but it can happen and the reason seems to be physiologic. Sometimes the plant "decides to produce flower buds" more than once in the same axil. So you can have more than one reproductive bud later developing flower clusters in the same axil instead just of 1 vegetative (new leaf or branchlet) + 1 reproductive (new flower cluster). As the examples above depict, you can have 3 buds from the same axil, 1 vegetative (new leaf or branchlet) + 2 reproductive (2 new flower clusters). When happening, this variation normally affects just a small number of axils per plant.

Taxonomic implications

For E. globulus ssp. globulus, which normally produces only one flower bud per axil, this situation can be confusing because flower buds (and later seed capsules) are big sized and almost sessile (no clear peduncles). When a specimen of this subspecies "decides to produce paired inflorescences" it can be mistaken with "E. bicostata" (Eucalyptus globulus ssp. bicostata, which regularly produces flowers in groups of three).

Eucalyptus bicostata Eucalyptus globulus ssp. bicostata flower buds Eucalipto bicostata inflorescencia flores Mt Annan New South Wales Australia Phil Sydney GIT Forestry Consulting

Fig. 2: Example of E. bicostata flower buds collected at Mt Annan (NSW, Australia). Bud clusters are regularly grouped in 3's and smaller sized than in E. globulus ssp. globulus.

Some literature suggests this paired inflorescence feature can become a factor to identify other species but we are of the opinion some caution is needed when botanising samples since if this is a physiologic response it could happen in many other species. What would matter then is a careful inspection of botanical samples in order to identify which is the frequency of paired inflorescences in a certain flowering branch.

It is good keeping photographic record if you observe it in any eucalypt species. It is a curiousity!! Also, there is no need to say it will make a massive bunch of flowers, double the size of a normal cluster, which deserves even more photography.

Contact GIT Forestry Consulting - Eucalyptologics

If you observe this feat in any eucalypt around, do not be hesitate contacting us and share the photos!

Acknowledgements

Special thanks to Benoit Binson at Marennes (France) and Phil in Sydney (Australia) for their photographic contributions.

You can visit Phil's Blog "Eucalypts In Habitat" for some great views on NSW eucalypts.

GIT's Eucalyptology Topics