search.noResults

search.searching

dataCollection.invalidEmail
note.createNoteMessage

search.noResults

search.searching

orderForm.title

orderForm.productCode
orderForm.description
orderForm.quantity
orderForm.itemPrice
orderForm.price
orderForm.totalPrice
orderForm.deliveryDetails.billingAddress
orderForm.deliveryDetails.deliveryAddress
orderForm.noItems
TECHNICAL


Green roof


Why it is that science is always right but, simultaneously, often wrong and how critical analysis of the facts can help us make good decisions


process of writing peer reviewed articles. In this process, researchers submit an article to a journal but, before publication, it will be assessed by other experts within that subject area. Articles are often re-written several times before they are published and some never make it beyond the initial peer review process. This process ensures the academic rigour of articles that are published, but it is the material within the articles themselves that demonstrates the concept of critical thinking.


A practical example


As it is a subject that I know well, I will use my own PhD research as an example of this. My research was about green roofs which are a means of placing vegetation onto the rooftops of buildings, not with the aim of creating a garden but to stimulate positive environmental outcomes. For example, green roofs are thought to reduce the likelihood of flooding in urban area, reduce the urban heat island effect, reduce particulate and gaseous pollutants, improve building sound and heat insulation, and to increase biodiversity. With all these benefits, it is unsurprising that there has, in the


last ten or so years, been a considerable increase in the number of papers, including mine, published in this issue.


Way back in 2014, I published a paper in the journal, Ecological Engineering, entitled ‘Plant growth responses to different growing media for green roofs’ (Graceson, et al., 2014). One of the limiting factors in installing a green roof is the ability of a building to withstand the extra load placed upon it. Because of this, green roof design has focused on the use of relatively thin growing media layers (usually <150mm deep). These are made from a high proportion of inorganic granular materials, such as crushed brick, to minimise the extra weight on the building. Amongst other things, my work extended that of another research group who had contended that:


Increased fertility due to higher organic matter content may encourage excessive growth which cannot easily survive drought conditions (Nagase & Dunnett, 2011).


To expand upon this, I identified that, by utilising different materials for the inorganic component of the growing media, it is


possible to limit growth of some of the more enthusiastic plants. This allows for greater species diversity and introducing the possibility of increasing the amount of organic matter in the growing media. This would result in a lower overall bulk density and, therefore, increase the number of buildings that would be suitable for green roof installation.


Through critical thinking, I had extended the ideas within the original concept to generate one of those incremental changes:


Concept Mk 1. Growing media for green roofs must contain little organic matter to prevent excessive plant growth.


Concept Mk 2. Organic matter content in growing media for green roofs can be increased provided that another component will act to restrict plant growth.


There was nothing wrong with Concept Mk 1, it was simply created using the best knowledge available at the time. Its creation enabled the development of Concept Mk 2 which will, in turn, enable the creation of Concept Mk 3, and so the development of ideas continues.


So, as you read or hear about the latest ideas from the scientific world, please don’t dismiss them out of hand, they will almost certainly be the best we can come up with at the moment. Perhaps, in time, those ideas will be rewritten but our best hopes of improvement lies in our ability to think critically.


References


Cottrell, S., 2005. Critical thinking skills - developing effective analysis and argument. UK: Palgrave Macmillan.


Graceson, A., Monaghan, J., Hall, N. & Hare, M., 2014. Plant growth responses to different growing media for green roofs. Ecological Engineering, Volume 69, pp. 196-200.


Nagase, A. & Dunnett, N., 2011. The relationship between percentage of organic matter in substrate and plant growth in extensive green roofs. Landscape and urban planning, 103(2), pp. 230-236.


PC June/July 2020 123





Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156