ISA Certified Arborist Prepatory Programme (Singapore) and ISA Certified Arborist Application (US and Other Countries)

About 8 years ago, it was acceptable to have a diploma in arboriculture or equivalent, plus 2 years of relavent experience in order to be accepted into the ISA Certified Arborist Prepartory Programme (see Table 1). This is programme is a series of classes facilitated by the National Parks Board in Singapore, which a candidate could go through before taking the exams to become an ISA Certified Arborist. Taking the classes could increase the chances that the candidate would pass the exams. Fast forward 5 years, around year 2017, the prerequisite changed to that of a two-year degree in arboriculture plus two years of practical experience. How many people in Singapore would have such a degree and even if one had the inclination to attain it, one would have to obtain it overseas. As for the four-year degree "in a related field" - what would constitute as related?

Table 1. Comparison between the requirements in 2012 and prerequisites in 2020 for the entry into Singapore's ISA Certified Arborist Prepartory Programme.

In the US and other countries, their statutory boards does not organise prepartory programmes for potential ISA certified Arborists, but rather the country Chapters, associate organisations or interest groups. ISA just administer the applications, exams and certification. It has stated the eligibility of candidates who wish to apply for the exam (see Table 2). Almost the same as the Singapore requirements, ISA require degree holders to have either a two-year associate degree with 2 years practical experience or four-year bachelor degree with 1 year practical experience. But what is lacking in the Singapore requirements is the "Assessment-Based Certificate Programs (Diplomas, Certificates)" category. "900 hours of assessed training" could be roughly 1 year of full-time study/training, and 1800 hours of assessed training could be roughly 2 years of full-time study/training.

Is the ISA Certified Arborist Prepartory Programme in Singapore leaving out candidates who do not have two-year or four-year degrees?

Table 2. Comparison between the eligibility to apply for the ISA Certified Arborist exam and prerequisites in 2020 for the entry into Singapore's ISA Certified Arborist Prepartory Programme.

Avocado Trouble Shooting

A homeowner planted three avocado trees on his property, and his are the only avocado trees in his neighbourhood but they are not fruiting. The varieties are Hass, Gwen and Pinkerton, as he is after the flavour and had a aversion to green skinned varieties. The trees were flowering as usual, and the foliage were green and does not show signs of drought stress.

Avocado trees have perfect flowers meaning the male and female parts are in the same flower, so Dendro's assistant was wondering if it could self-pollinate. Dendro explained that the male and female part are not active on the same tree at the same time, a flowering behavior known as synchronous dichogamy. There are two types of varieties: A-varieties that open their flowers as female in the morning and as male in the afternoon, and B-varieties that open their flowers in a vice-versa manner. During the male phase, the stamen is upright and during the female phase, the stamen lays flat around the stigma.

The detectives observed that the client's trees are A-varieties, as their visit was in the afternoon and the stamens are all upright. The three varieties planted by the client were determined to be A-varieties, and cannot fruit without B-varieties around. Dendro explained that more A-varieties are cultivated but B-varieties are necessary to pollination.

Hence, if the client wishes for his trees to bear fruit, he would have to plant B-varieties like Bacon, Fuerte or Zutano. A new breeding program from the University of California is evaluating two new B-varieties - 'Nobel' and 'Marvel' - that produces a black, Hass-like fruit.

Additional reading: Arpaia, M.L., A.E. Fetscher, and R. Hofshi. Avocado Flowering Basics. University of California Agriculture & Natural Resources. http://ucavo.ucr.edu/Flowering/FloweringBasics.html