Giants Grove Forest Maintenance

Written by Sean

September 29, 2020

Over 500 years ago Chaucer wrote that ‘an ook cometh of a litel spyr’, and although the language has changed, it is still true that tall oaks from little acorns grow. Of course it’s not only oaks but all the majestic trees we see today had humble beginnings, and it’ll be true for the Redwoods in the Giants Grove too.

What few of us realise though, are the odds every impressive tree we see have overcome to realise their full potential. Young trees are weak and vulnerable, and so constant supervision and good forest maintenance is essential to ensure saplings survive to become Giants.

Vegetation Control:

This is required to protect a specimen from competing vegetation. Competition for light, water and nutrients can significantly impact growth, and may often result in death. Chemical control may be used for particularly aggressive weeds, but it is non-selective and can damage beneficial flora, or improper application could even kill the tree being protected. Also, many chemicals are harmful to the environment, so we do not use chemicals in the Giants Grove. We use manual grasscleaning, this is where we cut or trample competing vegetation as required once or twice a year. The results are short-term, but do no harm to the environment, and this will only be required during the early establishment phase.

Formative Shaping/Pruning:

This is the selective removal of forks, large competing side branches, or dead/damaged branches. It concentrates the trees growth into a single straight stem allowing them to escape competition sooner, and it keeps the tree healthy. It’s important not to remove any more than is absolutely necessary though, or growth will be slowed considerably.


Although the soil in the giants Grove was tested prior to planting, it’s important to keep a close eye on nutritional requirements throughout the site. Nitrogen, Phosphorus and Potassium are the most important nutrients for trees, but micronutrients such as iron, zinc, copper etc. are also essential. Any specific deficiencies the trees may have are expressed in specific ways – dull foliage, yellowing, leaf sizes, etc., and so a fertiliser application can remedy any problems quickly once discovered.


Although Sequoia and Sequoiadendron rarely suffer from pests, they remain susceptible to scale insect infestations, and the diverse nurse species in the Giants Grove could be hit by a range of other insects or diseases. We don’t expect any infestations in the Grove, but we keep a close eye out for them anyway because early detection is essential. Deer may also be a pest in young forests, and although we welcome them we have to work hard to prevent any damage from browsing, fraying or bark stripping.

Redwoods are among the fastest growing trees on earth, and the Giants Grove at Birr Castle is an optimum site for them in which to reach their full potential. In the right conditions these trees can grow well over 1.5m in height and 2cm in girth every year, and they grow faster every year as they get older. All of us here in the Giants Grove Project are doing the little forest maintenance needed so we can see just how big our Giants can get!

The Giants Grove Project is an Partnership between Birr Castle Estate and Crann – Trees for Ireland

To sponsor a Giant, learn more on our Sponsor a Giant page, or contact us at 

Sean McGinnis Ecoplan Forestry

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